As a follow-up of https://tracker.moodle.org/browse/MDL-74514, we need to revisit the way we define the variable as the polling is not only used for the "wait for moderator" feature.

Ideally, we should be polling in a long(er) interval and using the data that the cache provides for most cases (wait for moderator, status of the meeting etc).

The only case that forces a new poll and updating the cache is when a juster hits the button to Join a meeting. In that case, there should be an update after a few secs of the button clicked as the users not necessarily get into the BBB session immediately.