feat: added persistent config item to redis handler Session

[ddevsr]

Description
Needed #9792

Checklist:

• Securely signed commits
• Component(s) with PHPDoc blocks, only if necessary or adds value (without duplication)
• Unit testing, with >80% coverage
• User guide updated
• Conforms to style guide

[neznaika0]

@ddevsr wait for the first PR to be accepted. There is no need to send an additional one in advance. What if your first PR changes?
Besides, it's not clear what exactly you're changing in this PR.

[michalsn]

Can we include this in the user guide? The following spot seems appropriate: https://github.com/codeigniter4/CodeIgniter4/blob/4.7/user_guide_src/source/libraries/sessions.rst?plain=1#L719-L721

Something like:

Starting with v4.7.0, you can define a persistent connection::
public string $savePath = 'tcp://localhost:6379?persistent=1';

[michalsn]

Maybe we can do something like filter_var($query['persistent'], FILTER_VALIDATE_BOOLEAN) instead of just casting to bool? Although if we document this property, we can leave it as it is.