Prevent deleting Code Components if there are usages in forward revisions

Overview

📌 Only allow deleting Code Components if there's 0 usages Active made it so that Canvas prevents you from deleting Code Components if they are being used on a Page's draft content that's in auto-save storage, but does not prevent that if that same draft content is in a forward revision instead of auto-save storage. That makes no sense: for the purpose of considering a Code Component as "in use", draft content should count the same whether it's in auto-save storage or in a forward revision.

Proposed resolution

Add onto the code that was added in 📌 Only allow deleting Code Components if there's 0 usages Active to also query forward revisions for usage.

User interface changes