[#147] Pass context to user selectors

[matthewhilton]

Closes #147

Simple fix for issue, just passing in the correct context. Note the context is course context, not course module context, because this appears to be what the rest of the page is using.

Testing
Logged in as user with moodle/site:viewuseridentity in course context, but not system context. showuseridentity config has email selected to show. On the attendees sign up page.

Before (no emails shown):

After (emails shown - good):

TODO

• Cherry pick to other branches -> [#147] Pass context to user selectors #149