Add checks for profanity to profile updates (#12445)

* fix(profile): detect attempt to use banned words as display name. refactor profanity detection method.

* fix(profile): detect attempt to use banned words in blurb. further refactor profanity detection. inform the user their chat privileges have been revoked.

* refactor: add function to normalize Unicode strings and remove diacritics

* fix: improve regEx to prevent false partial matches e.g. 'hello' being recognised as banned words. porting fix from #12309

* fix(profile): refactor of profanity detection for #12445

* fix(profile): add test for swear words in new profile. fix existing tests

* fix(profile): show different error message for attempted slur use in username by new users.

* fix(profile): remove incorrect slur test

* fix(profile): fix slurs not caught at start of end of strings connect by punctuation

* tests(profile): fix tests for profanity checking

* remove exclusive test

* 11865 - update text for slur warnings

* 11865 - remove unused string from locale files

* 11865 - improve naming of banned word usage locale string

* 11865 - improve logic so that differentiated warnings are shown depending on whether a slur or other profanity has been used in a display name

* 11865 - construct slur regexes outside the validation function in which they are used

* 11865 - fix tests

website/server/controllers/api-v3/auth.js

@@ -213,7 +213,7 @@ api.updateUsername = {
 
     const newUsername = req.body.username;
 
-    const issues = verifyUsername(newUsername, res);
+    const issues = verifyUsername(newUsername, res, false);
     if (issues.length > 0) throw new BadRequest(issues.join(' '));
 
     const { password } = req.body;