Include IntegerArrayTypeToList from worker_protocol.h instead of array_type.h

On Citus versions <= 11.0, IntegerArrayTypeToList() doesn't exist and
its helpers (DeconstructArrayObject() & ArrayObjectCount()) are defined
in worker_protocol.h. (See 9476f377b5).

So we add IntegerArrayTypeToList() into worker_protocol.c and include
IntegerArrayTypeToList from worker_protocol.h instead of array_type.h
in foreign_constraint.c.

This is needed to backport a868cc049a into
this (release-11.0) branch, see the next commit.

src/backend/distributed/worker/worker_partition_protocol.c

@@ -419,6 +419,26 @@ ArrayObjectCount(ArrayType *arrayObject)
 }
 
 
+/*
+ * Converts ArrayType to List.
+ */
+List *
+IntegerArrayTypeToList(ArrayType *arrayObject)
+{
+	List *list = NULL;
+	Datum *datumObjectArray = DeconstructArrayObject(arrayObject);
+	int arrayObjectCount = ArrayObjectCount(arrayObject);
+
+	for (int index = 0; index < arrayObjectCount; index++)
+	{
+		int32 intObject = DatumGetInt32(datumObjectArray[index]);
+		list = lappend_int(list, intObject);
+	}
+
+	return list;
+}
+
+
 /*
  * InitTaskDirectory creates a job and task directory using given identifiers,
  * if these directories do not already exist. The function then returns the task

src/include/distributed/worker_protocol.h

@@ -118,6 +118,7 @@ extern StringInfo InitTaskDirectory(uint64 jobId, uint32 taskId);
 extern void RemoveJobSchema(StringInfo schemaName);
 extern Datum * DeconstructArrayObject(ArrayType *arrayObject);
 extern int32 ArrayObjectCount(ArrayType *arrayObject);
+extern List * IntegerArrayTypeToList(ArrayType *arrayObject);
 extern FmgrInfo * GetFunctionInfo(Oid typeId, Oid accessMethodId, int16 procedureId);
 extern uint64 ExtractShardIdFromTableName(const char *tableName, bool missingOk);
 extern void RepartitionCleanupJobDirectories(void);