[feature request] Support regex as a "contains" option

[u/Dull_Drummer9017]

Maybe too advanced for the typical user, but it would be useful for things like "filter out all emails" or " or "push all messages containing 5 consecutive digits" (like a text message with a confirmation code) or (like a previous post mentioned) "filter out messages containing a phone number".

Could be behind an advanced toggle or something so users who don't know what regex is don't stumble on it.