[Feature] cdc add case_sensitive config

### Search before asking

- [X] I searched in the [issues](https://github.com/apache/incubator-paimon/issues) and found nothing similar.

### Motivation

Through flame diagrams, it was found that there is a significant performance loss in handling field capitalization during the parse phase

The default behavior in MySQL is that field names are case-insensitive. Any sensitivity considerations should be configured by the user rather than determined based on the catalog

### Solution

_No response_

### Anything else?

_No response_

### Are you willing to submit a PR?

- [X] I'm willing to submit a PR!

No files, tests, or implementation entry points are named. Start by locating the CDC parsing and configuration entry points, then clarify the intended case_sensitive behavior and verify how MySQL field-name handling currently works. Done should include the user-facing configuration and coverage for both sensitivity settings.

Written by the indexing model from the issue text.