Need to use the get_user_language() function in activity to work out right language to send message in

[Robert Lyon]

Currently the activity.php way of finding language is ignoring the option when user is in an institution that has a specific language set, but the user themselves has no specific language set.

activity.php is defaulting to site language rather than institution language.

[Mahara Bot (dev-mahara)]

Reviewed: https://reviews.mahara.org/11466
Committed: https://git.mahara.org/mahara/mahara/commit/311320c6ef1d191e40994a615da78f43faf49da2
Submitter: Lisa Seeto (<email address hidden>)
Branch: master

commit 311320c6ef1d191e40994a615da78f43faf49da2
Author: Robert Lyon <email address hidden>
Date: Mon Nov 23 12:51:36 2020 +1300

Bug 1905477: Fixing problem where default lang was institution lang

and not site lang

To test: Have a person in an institution where the institution language
is not English. Make sure the lang pack has translations for the
strings to test. Make sure the person doesn't have their lang set in
usr_account_preferences table - so they are defaulting to the
institution default.

Share a collection to that person from another person in an
institution that uses english

The message should be in the language of the receiver

Change-Id: Icddc90c3b7bd8279d37e16b4de171631c4020268
Signed-off-by: Robert Lyon <email address hidden>