[cleanup][txn] Avoid unnessary method call if txn disabled.

[lifepuzzlefun]

Fixes #18324

Motivation

avoid unnecessary method call if txn disabled.

Modifications

1. remove isTxnEnabled parameter in TransactionBuffer.checkIfTransactionBufferRecoverCompletely.
2. check isTxnEnabled before call txn related code in common code path.
3. remove unused constructor of PersistentTopic

Verifying this change

This change is a trivial rework / code cleanup without any test coverage.

Does this pull request potentially affect one of the following parts:

If the box was checked, please highlight the changes

• [ ] Dependencies (add or upgrade a dependency)
• [ ] The public API
• [ ] The schema
• [ ] The default values of configurations
• [ ] The threading model
• [ ] The binary protocol
• [ ] The REST endpoints
• [ ] The admin CLI options
• [ ] Anything that affects deployment

Documentation

• [ ] doc
• [ ] doc-required
• [x] doc-not-needed
• [ ] doc-complete

[github-actions[bot]]

@WJL3333 Please add the following content to your PR description and select a checkbox:

- [ ] `doc` <!-- Your PR contains doc changes -->
- [ ] `doc-required` <!-- Your PR changes impact docs and you will update later -->
- [ ] `doc-not-needed` <!-- Your PR changes do not impact docs -->
- [ ] `doc-complete` <!-- Docs have been already added -->

[lifepuzzlefun]

@codelipenghui @congbobo184 please take a look, thank you~

[poorbarcode]

@congbobo184 Could you take a look?

[github-actions[bot]]

The pr had no activity for 30 days, mark with Stale label.

[tisonkun]

Closed as stale. Also, code can be written in multiple styles. Such changes without a clear style rule are not converged. Generally, who write the functionality or fix a bug make the call on the style of his/her code snippet.