fix(e2e): always clean up mysql.rds_configuration table via t.Cleanup

Register DROP TABLE in t.Cleanup at the start of TestMySQLRDSBinlogValidation
so the table is guaranteed to be dropped even if the test fails early (e.g.
due to an assertion mismatch). Without this, a test failure before the
inline DROP TABLE left mysql.rds_configuration with a NULL value, causing
all subsequent parallel MySQL tests to fail with the RDS binlog retention
validation error.

Co-authored-by: Pablo Francisco Pérez Hidalgo <pfcoperez@users.noreply.github.com>

Author: github-actions[bot]

flow/e2e/mysql_rds_binlog_test.go

@@ -72,6 +72,11 @@ func TestMySQLRDSBinlog(t *testing.T) {
 }
 
 func (s MySQLRDSBinlogAPITestSuite) TestMySQLRDSBinlogValidation() {
+	// Register cleanup before creating the table so it is always dropped even if the test fails early.
+	s.t.Cleanup(func() {
+		_ = s.source.Exec(context.Background(), "DROP TABLE IF EXISTS mysql.rds_configuration")
+	})
+
 	require.NoError(s.t, s.source.Exec(s.t.Context(),
 		fmt.Sprintf("CREATE TABLE %s(id int primary key, val text)", AttachSchema(s, "valid"))))
 
@@ -109,6 +114,4 @@ func (s MySQLRDSBinlogAPITestSuite) TestMySQLRDSBinlogValidation() {
 	res, err = s.ValidateCDCMirror(s.t.Context(), &protos.CreateCDCFlowRequest{ConnectionConfigs: flowConnConfig})
 	require.NoError(s.t, err)
 	require.NotNil(s.t, res)
-
-	require.NoError(s.t, s.source.Exec(s.t.Context(), "DROP TABLE IF EXISTS mysql.rds_configuration;"))
 }