[Schema] Fix parse BigDecimal (#14019)

### Motivation

I can use Avro schema with BigDecimal in Pulsar 2.8.0, but this doesn't work on Pulsar 2.8.1, so I check this codebase and PR, found #10428 breaks this.

The following is error log:
```
org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:154) ~[spring-beans-5.3.4.jar:5.3.4]
	... 34 common frames omitted
Caused by: java.lang.UnsupportedOperationException: No recommended schema for decimal (scale is required)
	at org.apache.pulsar.shade.org.apache.avro.Conversions$DecimalConversion.getRecommendedSchema(Conversions.java:73) ~[pulsar-client-2.8.1.jar:2.8.1]
	at org.apache.pulsar.shade.org.apache.avro.reflect.ReflectData.createSchema(ReflectData.java:696) ~[pulsar-client-2.8.1.jar:2.8.1]
	at org.apache.pulsar.shade.org.apache.avro.reflect.ReflectData.createFieldSchema(ReflectData.java:873) ~[pulsar-client-2.8.1.jar:2.8.1]
	at org.apache.pulsar.shade.org.apache.avro.reflect.ReflectData$AllowNull.createFieldSchema(ReflectData.java:92) ~[pulsar-client-2.8.1.jar:2.8.1]
	at org.apache.pulsar.shade.org.apache.avro.reflect.ReflectData.createSchema(ReflectData.java:736) ~[pulsar-client-2.8.1.jar:2.8.1]
	at org.apache.pulsar.shade.org.apache.avro.specific.SpecificData$3.computeValue(SpecificData.java:328) ~[pulsar-client-2.8.1.jar:2.8.1]
	at org.apache.pulsar.shade.org.apache.avro.specific.SpecificData$3.computeValue(SpecificData.java:325) ~[pulsar-client-2.8.1.jar:2.8.1]
	at java.base/java.lang.ClassValue.getFromHashMap(ClassValue.java:228) ~[na:na]
	at java.base/java.lang.ClassValue.getFromBackup(ClassValue.java:210) ~[na:na]
	at java.base/java.lang.ClassValue.get(ClassValue.java:116) ~[na:na]
	at org.apache.pulsar.shade.org.apache.avro.specific.SpecificData.getSchema(SpecificData.java:339) ~[pulsar-client-2.8.1.jar:2.8.1]
	... 52 common frames omitted
```

I think that Avro cannot work on using the ReflectData with Conversions.DecimalConversion to parse the BigDecimal field without AvroSchema when getting schema, but the Avro ReflectDatumWriter and ReflectDatumReader are working, it seems that Avro support for BigDecimal is not enough.

Affected version: 2.8.1...2.8.x, 2.9.x

### Modifications

- Skip add the DecimalConversion in `extractAvroSchema()`

(cherry picked from commit 2ca8e8a)

pulsar-client/src/main/java/org/apache/pulsar/client/impl/schema/AvroSchema.java

@@ -106,7 +106,14 @@ public static <T> AvroSchema<T> of(Class<T> pojo, Map<String, String> properties
     }
 
     public static void addLogicalTypeConversions(ReflectData reflectData, boolean jsr310ConversionEnabled) {
-        reflectData.addLogicalTypeConversion(new Conversions.DecimalConversion());
+        addLogicalTypeConversions(reflectData, jsr310ConversionEnabled, true);
+    }
+
+    public static void addLogicalTypeConversions(ReflectData reflectData, boolean jsr310ConversionEnabled,
+                                                 boolean decimalConversionEnabled) {
+        if (decimalConversionEnabled) {
+            reflectData.addLogicalTypeConversion(new Conversions.DecimalConversion());
+        }
         reflectData.addLogicalTypeConversion(new TimeConversions.DateConversion());
         reflectData.addLogicalTypeConversion(new TimeConversions.TimeMillisConversion());
         reflectData.addLogicalTypeConversion(new TimeConversions.TimeMicrosConversion());

pulsar-client/src/main/java/org/apache/pulsar/client/impl/schema/util/SchemaUtil.java

@@ -94,7 +94,7 @@ public static Schema extractAvroSchema(SchemaDefinition schemaDefinition, Class
             ReflectData reflectData = schemaDefinition.getAlwaysAllowNull()
                      ? new ReflectData.AllowNull()
                      : new ReflectData();
-            AvroSchema.addLogicalTypeConversions(reflectData, schemaDefinition.isJsr310ConversionEnabled());
+            AvroSchema.addLogicalTypeConversions(reflectData, schemaDefinition.isJsr310ConversionEnabled(), false);
             return reflectData.getSchema(pojo);
         }
     }

pulsar-client/src/test/java/org/apache/pulsar/client/impl/schema/AvroSchemaTest.java

@@ -36,7 +36,6 @@
 import java.time.temporal.ChronoUnit;
 import java.util.Arrays;
 import java.util.UUID;
-
 import lombok.Data;
 import lombok.extern.slf4j.Slf4j;
 import org.apache.avro.Schema;
@@ -438,4 +437,26 @@ public void testAvroUUID() {
         assertEquals(pojo1.uid, pojo2.uid);
     }
 
+    static class MyBigDecimalPojo {
+        public BigDecimal value1;
+        @org.apache.avro.reflect.AvroSchema("{\n" +
+                "  \"type\": \"bytes\",\n" +
+                "  \"logicalType\": \"decimal\",\n" +
+                "  \"precision\": 4,\n" +
+                "  \"scale\": 2\n" +
+                "}")
+        public BigDecimal value2;
+    }
+
+    @Test
+    public void testAvroBigDecimal() {
+        org.apache.pulsar.client.api.Schema<MyBigDecimalPojo> schema =
+                org.apache.pulsar.client.api.Schema.AVRO(MyBigDecimalPojo.class);
+        MyBigDecimalPojo myBigDecimalPojo = new MyBigDecimalPojo();
+        myBigDecimalPojo.value1 = new BigDecimal("10.21");
+        myBigDecimalPojo.value2 = new BigDecimal("10.22");
+        MyBigDecimalPojo pojo2 = schema.decode(schema.encode(myBigDecimalPojo));
+        assertEquals(pojo2.value1, myBigDecimalPojo.value1);
+        assertEquals(pojo2.value2, myBigDecimalPojo.value2);
+    }
 }