Merge branch 'rs-remove-default-fingerprinting' into 'master'

Remove default from custom Sentry fingerprinting

See merge request gitlab-org/gitlab!29609

lib/gitlab/error_tracking.rb

@@ -186,7 +186,7 @@ module Gitlab
 
         return event unless CUSTOM_FINGERPRINTING.include?(ex.class.name)
 
-        event.fingerprint = ['{{ default }}', ex.class.name, ex.message]
+        event.fingerprint = [ex.class.name, ex.message]
 
         event
       end