FEATURE: topic is validated for blocked words (PR #8127)

Currently, the topic is only validated for censored words and should be validated for blocked words as well.

Blocked words validation is now used by both Post and Topic. To avoid code duplication, I extracted blocked words validation code into separate Validator, and use it in both places.

The only downside is that even if the topic contains blocked words validation message is saying “Your post contains a word that’s not allowed: tomato” but I think this is descriptive enough.

GitHub

You’ve signed the CLA, lis2. Thank you! This pull request is ready for review.

This looks good to me!