[cdc] Fix bug that computed columns work abnormally with case-insensitive

[yuzelin]

Purpose

We cannot retrieve schema with case sensitive because the computed columns rely on the original schema.
I refactor the flow:

1. case-sensitive is not involved in the validation, schema retrieving and computed columns building phases;
2. building Paimon schema uses case-sensitive;
3. when parsing records, first we parse all field and evaluate all computed columns, and then we apply case-sensitive conversion.

Tests

KafkaCanalSyncTableActionITCase#testComputedColumnWithCaseInsensitive
MongoDBSyncTableActionITCase#testComputedColumnWithCaseInsensitive
MySqlSyncTableActionITCase#testComputedColumnWithCaseInsensitive
MySqlSyncTableActionITCase#testSpecifyKeysWithCaseInsensitive

API and Format

Documentation

[JingsongLi]

+1