[ticket/12809] Fix select button and dropdown list items in RTL.

PHPBB3-12809
[ticket/12809] Remove obsolete rules and selector.

PHPBB3-12809
[ticket/12809] Restore text-align for the pagination.

PHPBB3-12809
Merge pull request #2714 from prototech/ticket/12809

[ticket/12809] Fix select button and dropdown list items in RTL.