Fix audio and push alerts for user join

Add avatar back to chat poll result message

Quick poll improvements

Fix clear chat for single message

Add reconnection and sync handler

numUsersVideo being undefined breaks layout

Fix svg width error

Revert custom changes to settings.yml

Inadvertently introduced by #11514

Add some extra docs/setup instructions to the analytics callback script

Adds tests recording + updates some outdated tests + linting

External video events propagated through akka-apps

When validating tokens, the dummyUser created at the beginning is set
with validated=true. This means there won't be the state change that used
to occur from validated:false to validated:true (which detects the moment
joined the meeting) , therefore the alert code that expects for this change
won't run.
To fix this for audio alerts, we now detect when user join by observing
additions in Users's collection. This is actually good because we start
observing this only once (in componentDidMount), differently we used to do,
by calling this every time the tracker was activated.

To distinguish between the user addition that initially populates user's
collection from those that happens after user join (which are the ones we
want), we store the initial state (at componentDidMount) and compare it
with new additions. If the user added is present at the initial state,
then it is an addition to populates the collection, otherwise this is a real
user addition (happened after user joined the meeting)

Partially fixes #11399

Adds lastAuthTokenValidatedOn to users

Fix chat textarea resizing bug

Fix chat messages timestamp

Breakout room audio fixes

Fix mobile user removal bug

Without 'exact' match, the browser fallbacks to the default inputDeviceId

This prevents the error (input device error)  when breakout is ended and we try
to skipCheck the microphone when user returns to main room (assuming the
user had the microphone active before joining breakout room). Related
to the feature c451666d

Fixes #11511
Related to the feature implemented in c451666d