Remove readInternalProperties helpers (#2506)

the functionality is already provided by the `PrincipalEntity`

Author: XN137

runtime/service/src/test/java/org/apache/polaris/service/test/PolarisIntegrationTestFixture.java

@@ -21,8 +21,6 @@
 import static org.apache.polaris.service.context.TestRealmContextResolver.REALM_PROPERTY_KEY;
 import static org.assertj.core.api.Assertions.assertThat;
 
-import com.fasterxml.jackson.core.JsonProcessingException;
-import com.fasterxml.jackson.core.type.TypeReference;
 import jakarta.ws.rs.client.Client;
 import jakarta.ws.rs.client.ClientBuilder;
 import jakarta.ws.rs.client.Entity;
@@ -113,9 +111,8 @@ private PolarisPrincipalSecrets fetchAdminSecrets() {
     PolarisMetaStoreManager metaStoreManager =
         helper.metaStoreManagerFactory.getOrCreateMetaStoreManager(realmContext);
     PrincipalEntity principal = metaStoreManager.findRootPrincipal(polarisContext).orElseThrow();
-    Map<String, String> propertiesMap = readInternalProperties(principal);
     return metaStoreManager
-        .loadPrincipalSecrets(polarisContext, propertiesMap.get("client_id"))
+        .loadPrincipalSecrets(polarisContext, principal.getClientId())
         .getPrincipalSecrets();
   }
 
@@ -213,15 +210,6 @@ public void destroy() {
     }
   }
 
-  private Map<String, String> readInternalProperties(PrincipalEntity principal) {
-    try {
-      return helper.objectMapper.readValue(
-          principal.getInternalProperties(), new TypeReference<>() {});
-    } catch (JsonProcessingException e) {
-      throw new RuntimeException(e);
-    }
-  }
-
   private static SnowmanIdentifier getSnowmanIdentifier(TestEnvironment testEnv) {
     return new SnowmanIdentifier("snowman" + testEnv.testId(), "catalog-admin" + testEnv.testId());
   }

runtime/service/src/test/java/org/apache/polaris/service/test/PolarisIntegrationTestHelper.java

@@ -18,7 +18,6 @@
  */
 package org.apache.polaris.service.test;
 
-import com.fasterxml.jackson.databind.ObjectMapper;
 import jakarta.inject.Inject;
 import jakarta.inject.Singleton;
 import org.apache.polaris.core.PolarisDiagnostics;
@@ -32,7 +31,6 @@ public class PolarisIntegrationTestHelper {
 
   @Inject MetaStoreManagerFactory metaStoreManagerFactory;
   @Inject RealmContextResolver realmContextResolver;
-  @Inject ObjectMapper objectMapper;
   @Inject PolarisDiagnostics diagServices;
   @Inject PolarisConfigurationStore configurationStore;