[opt](table) Remove unnecessary locks (#44416)

`OlapTable`.`getPartitionIds` not need get readLock, Because it only
returns the ID list without any traversal or other operations. If the
caller needs to keep the partition of the table unchanged after
obtaining the ID list, they should lock it themselves

fe/fe-core/src/main/java/org/apache/doris/catalog/OlapTable.java

@@ -1385,12 +1385,7 @@ public List<String> getEqualPartitionNames(List<Long> partitionIds1, List<Long>
     }
 
     public List<Long> getPartitionIds() {
-        readLock();
-        try {
-            return new ArrayList<>(idToPartition.keySet());
-        } finally {
-            readUnlock();
-        }
+        return new ArrayList<>(idToPartition.keySet());
     }
 
     public Set<String> getCopiedBfColumns() {