Update clear_active_connections! to resolve deprecation warning in activerecord 7.1

[AndreasBaumgart]

With activerecord (= 7.1.1), the following deprecation warning is received on master:

DEPRECATION WARNING: Calling `ActiveRecord::Base.clear_active_connections! is deprecated. Please call the method directly on the connection handler; for example: `ActiveRecord::Base.connection_handler.clear_active_connections!`

This PR replaces the call to ActiveRecord::Base.clear_active_connections! with the now recommended method ActiveRecord::Base.connection_handler.clear_active_connections!. This change ensures compatibility with future versions of ActiveRecord and follows current recommendations.

[tomgi]

Cool!

I noticed there's another deprecation warning related to the same method:
DEPRECATION WARNING: clear_active_connections! currently only applies to connection pools in the current role (writing). In Rails 7.2, this method will apply to all known pools, regardless of role. To affect only those connections belonging to a specific role, pass the role name as an argument. To switch to the new behavior, pass :all as the role name. (called from call at /app/.bundle/ruby/3.2.0/bundler/gems/shoryuken-869fb0c77f8e/lib/shoryuken/middleware/server/active_record.rb:8)

@AndreasBaumgart Do you think we could fix them both at once?

[tomgi]

@AndreasBaumgart I combined your fix with the second deprecation warning fix, and a backward-compatibility with older version of rails

Have a look if you want to pull these changed into your PR master...tomgi:que:activerecord_deprecation_warning

[filipegiusti]

@tomgi, given @AndreasBaumgart has been unresponsive, it would be nice if you could open a new PR with you changes.