Merge branch 'MDL-72283_allow-customisation-of-redis-session-handler-errors' of https://github.com/ziegenberg/moodle

The 'unable to obtain session lock'-exception raised by the Redis
session handler is hardcoded in English and not all that useful
to the end user.

This change adds the error message to the lang/error.php and gives
the user further hints why the error might have occured and how it
could be fixed.

Signed-off-by: Daniel Ziegenberg <daniel@ziegenberg.at>

* No need to enclose the title of the quiz navigation fake block in
a span tag. The block title also gets appended to the skip link which
means that a block title with a span tag assigned with an identifier
can cause duplicate ID errors on the DOM.

    Display more friendly messages when:
    * When displaying activity and the server is not available
    * When we join a meeting and the server is not available or an error is detected

Prior to this change, the testcase would assert ordering based on
identical fields which could lead to random failures. Set distinct
next start time of course backup, and also remove random ordering
by sorting on defined course order (all other fields being equal).

To show inactive/unavailable rows '.dimmed_text' class usages have been replaced with '.text-muted'.

Paul Holden authored Dec 07, 2021 and Mikel Martín Corrales committed May 16, 2022

Given that custom reports can now have defined pagesize properties, we
need to preserve that value in the table filterset so that it's always
available after AJAX requests.