qt5: don't build tests.

Signed-off-by: Mike McQuaid <mike@mikemcquaid.com>
qt5: fix optionally building docs.

Closes #25414.

Signed-off-by: Mike McQuaid <mike@mikemcquaid.com>
qt: tweak docs arg formatting.
brew-test-bot: check requirements default_formulae

With this brew-test-bot doesn't skip builds, if a requirement isn't
satisfied but a default_formula is specified.

This default_formula is already in dependencies, because of brew deps.

Closes #25398.

Signed-off-by: Mike McQuaid <mike@mikemcquaid.com>