[FLINK-34403][ci] Transforms VeryBigPbProtoToRowTest into an integration test

The integration test configuration enables a bigger for test execution.

Author: XComp

flink-formats/flink-protobuf/src/test/java/org/apache/flink/formats/protobuf/VeryBigPbProtoToRowTest.java flink-formats/flink-protobuf/src/test/java/org/apache/flink/formats/protobuf/VeryBigPbProtoToRowITCase.java

@@ -25,8 +25,11 @@
 /**
  * Test for very huge proto definition, which may trigger some special optimizations such as code
  * splitting and java constant pool size optimization.
+ *
+ * <p>Implementing this test as an {@code ITCase} enables larger heap size for the test execution.
+ * The current unit test execution configuration would cause {@code OutOfMemoryErrors}.
  */
-public class VeryBigPbProtoToRowTest {
+public class VeryBigPbProtoToRowITCase {
 
     @Test
     public void testSimple() throws Exception {