Remove hidden characters from form fields (#3597)

* Remove control and non-printable characters from form fields (server side)

* Update regex to properly filter out control characters only

* Add regex lib to requirements flie

* Fix regex in javascript (client side)

* add required unicode flag

requirements.txt

@@ -194,6 +194,8 @@ redis==3.5.3
     # via
     #   django-q
     #   django-redis
+regex==2022.8.17
+    # via -r requirements.in
 requests==2.28.1
     # via
     #   coreapi