* Remove duplicate copyright header
* Remove ts-ignores by just using the objects directly rather than via
event.target
* Use error.message rather than errorCode which TS doesn't know about
and may or may not exist.
* Remove some unused things like the skip rageshake function and
the option to init rageshakes without storage.
* Turn single function with a boolean param to make it take two entirely
separate code paths into two functions.
This is an Element project (in the vector-im repo) so the Copyright
should be for New Vector: it was incorrectly attributed to the
foundation for some files (and some files were missing headers).
