fix: use dynamic lockMaxRetries limit in RedisHandler

[gr8man]

Description

In RedisHandler::lockSession(), there was a bug where a hardcoded value of 300 was used to check if the maximum lock acquisition attempts were reached:

if ($attempt === 300) {

This bypassed the actual $this->lockMaxRetries property configured by the user. As a result, if a developer configured a smaller lockAttempts limit (e.g., 3), the check would fail to trigger because 3 !== 300, causing the method to incorrectly return true (success) despite not acquiring the lock. Conversely, it would hardcode the failure point to exactly 300 attempts regardless of higher configurations.

This PR replaces the hardcoded 300 with $this->lockMaxRetries in the condition and the associated error log message, ensuring the configured limits are appropriately enforced. A test has also been added to verify that the failure condition is triggered correctly after the maximum configured attempts.

Checklist:

• Secure coding practices
• Tests have been added to cover this change
• All tests pass

[michalsn]

Good catch. Some small changes are required, as well as adding a changelog entry here: https://github.com/codeigniter4/CodeIgniter4/blob/develop/user_guide_src/source/changelogs/v4.7.4.rst

[michalsn]

Please fix the changelog entry.

[michalsn]

Suggested change

	- **Session:** Fixed a bug in ``RedisHandler`` where missing ``$lockRetryInterval`` and ``$lockMaxRetries`` properties in a custom ``Session`` configuration file could trigger an ``Undefined property`` warning or error.
	- **Session:** Fixed a bug in ``RedisHandler`` where the configured ``$lockRetryInterval`` and ``$lockMaxRetries`` values were not respected when acquiring session locks.