remove unused containsApply check
remove unused containsApply check

Currently we will walk the tree for every single rule to see if an
`@apply` exists somewhere in that tree. However we don't use the
`containsApply` anymore so this is a quick win!

tailwindlabs/tailwindcss,tailwindlabs/tailwindcss,tailwindcss/tailwindcss,tailwindlabs/tailwindcss