container_at checks if the position provided matches the currently
focused container with view_container_at as a fast path.
view_container_at checks using the main container geometry, which
includes the titlebar and border area. If a tabbed container is focused,
then positions over unfocused tabs are incorrectly reported as belonging
to the focused container, breaking focus on click.
Add view_container_content_at for use in the focused container fast path
which only tests container content area, and fall back to full workspace
scans for border and titlebar areas.
Closes: https://github.com/swaywm/sway/issues/6074