feat: add BaseConnection::resetTransStatus()

[kenjis]

Description See #6909 https://github.com/codeigniter4/CodeIgniter4/pull/6886#issuecomment-1324182519

To restart transactions after strict mode failure.

Checklist:

• [x] Securely signed commits
• [x] Component(s) with PHPDoc blocks, only if necessary or adds value
• [ ] Unit testing, with >80% coverage
• [x] User guide updated
• [x] Conforms to style guide