[hotfix][transform][minor] Fix potential code conflict that SUBSTR built-in function is 1-based index now

This closes #3696

(cherry picked from commit 5184c01)

Author: yuxiqian

flink-cdc-composer/src/test/java/org/apache/flink/cdc/composer/flink/FlinkPipelineTransformITCase.java

@@ -505,7 +505,7 @@ void testBuiltinStringFunctions(ValuesDataSink.SinkApi sinkApi) throws Exception
                                         + "LOWER(name) AS col4, "
                                         + "TRIM(name) AS col5, "
                                         + "REGEXP_REPLACE(name, 'Al|Bo', '**') AS col6, "
-                                        + "SUBSTR(name, 0, 1) AS col7, "
+                                        + "SUBSTR(name, 1, 1) AS col7, "
                                         + "SUBSTR(name, 2, 1) AS col8, "
                                         + "SUBSTR(name, 3) AS col9, "
                                         + "CONCAT(name, ' - ', CAST(id AS VARCHAR)) AS col10",
@@ -516,13 +516,13 @@ void testBuiltinStringFunctions(ValuesDataSink.SinkApi sinkApi) throws Exception
                                 null)),
                 Arrays.asList(
                         "CreateTableEvent{tableId=default_namespace.default_schema.mytable1, schema=columns={`id` INT,`name` STRING,`age` INT,`col1` STRING,`col2` INT,`col3` STRING,`col4` STRING,`col5` STRING,`col6` STRING,`col7` STRING,`col8` STRING,`col9` STRING,`col10` STRING}, primaryKeys=id, options=()}",
-                        "DataChangeEvent{tableId=default_namespace.default_schema.mytable1, before=[], after=[1, Alice, 18, Dear Alice, 5, ALICE, alice, Alice, **ice, A, i, ce, Alice - 1], op=INSERT, meta=()}",
-                        "DataChangeEvent{tableId=default_namespace.default_schema.mytable1, before=[], after=[2, Bob, 20, Dear Bob, 3, BOB, bob, Bob, **b, B, b, , Bob - 2], op=INSERT, meta=()}",
-                        "DataChangeEvent{tableId=default_namespace.default_schema.mytable1, before=[2, Bob, 20, Dear Bob, 3, BOB, bob, Bob, **b, B, b, , Bob - 2], after=[2, Bob, 30, Dear Bob, 3, BOB, bob, Bob, **b, B, b, , Bob - 2], op=UPDATE, meta=()}",
+                        "DataChangeEvent{tableId=default_namespace.default_schema.mytable1, before=[], after=[1, Alice, 18, Dear Alice, 5, ALICE, alice, Alice, **ice, A, l, ice, Alice - 1], op=INSERT, meta=()}",
+                        "DataChangeEvent{tableId=default_namespace.default_schema.mytable1, before=[], after=[2, Bob, 20, Dear Bob, 3, BOB, bob, Bob, **b, B, o, b, Bob - 2], op=INSERT, meta=()}",
+                        "DataChangeEvent{tableId=default_namespace.default_schema.mytable1, before=[2, Bob, 20, Dear Bob, 3, BOB, bob, Bob, **b, B, o, b, Bob - 2], after=[2, Bob, 30, Dear Bob, 3, BOB, bob, Bob, **b, B, o, b, Bob - 2], op=UPDATE, meta=()}",
                         "CreateTableEvent{tableId=default_namespace.default_schema.mytable2, schema=columns={`id` BIGINT,`name` VARCHAR(255),`age` TINYINT,`description` STRING,`col1` STRING,`col2` INT,`col3` STRING,`col4` STRING,`col5` STRING,`col6` STRING,`col7` STRING,`col8` STRING,`col9` STRING,`col10` STRING}, primaryKeys=id, options=()}",
-                        "DataChangeEvent{tableId=default_namespace.default_schema.mytable2, before=[], after=[3, Carol, 15, student, Dear Carol, 5, CAROL, carol, Carol, Carol, C, r, ol, Carol - 3], op=INSERT, meta=()}",
-                        "DataChangeEvent{tableId=default_namespace.default_schema.mytable2, before=[], after=[4, Derrida, 25, student, Dear Derrida, 7, DERRIDA, derrida, Derrida, Derrida, D, r, rida, Derrida - 4], op=INSERT, meta=()}",
-                        "DataChangeEvent{tableId=default_namespace.default_schema.mytable2, before=[4, Derrida, 25, student, Dear Derrida, 7, DERRIDA, derrida, Derrida, Derrida, D, r, rida, Derrida - 4], after=[], op=DELETE, meta=()}"));
+                        "DataChangeEvent{tableId=default_namespace.default_schema.mytable2, before=[], after=[3, Carol, 15, student, Dear Carol, 5, CAROL, carol, Carol, Carol, C, a, rol, Carol - 3], op=INSERT, meta=()}",
+                        "DataChangeEvent{tableId=default_namespace.default_schema.mytable2, before=[], after=[4, Derrida, 25, student, Dear Derrida, 7, DERRIDA, derrida, Derrida, Derrida, D, e, rrida, Derrida - 4], op=INSERT, meta=()}",
+                        "DataChangeEvent{tableId=default_namespace.default_schema.mytable2, before=[4, Derrida, 25, student, Dear Derrida, 7, DERRIDA, derrida, Derrida, Derrida, D, e, rrida, Derrida - 4], after=[], op=DELETE, meta=()}"));
     }
 
     @ParameterizedTest