Make per tenant queue size reloadable during runtime

[yeya24]

Is your feature request related to a problem? Please describe.
We make max queue size a per tenant value in #4991. However, although they are per-tenant now, they are not dynamically updated during runtime because each user's queue is a buffered channel created during the initialization time. We should also update it during runtime.

Describe the solution you'd like
It is a little bit tricky here because we need to resize the channel, which means we need to handle increasing and shrinking channel size.

Describe alternatives you've considered
Maybe using an unbounded channel in this case is easier like https://github.com/smallnest/chanx.

[stale]

This issue has been automatically marked as stale because it has not had any activity in the past 60 days. It will be closed in 15 days if no further activity occurs. Thank you for your contributions.

[alanprot]

/remove stale

[stale]

This issue has been automatically marked as stale because it has not had any activity in the past 60 days. It will be closed in 15 days if no further activity occurs. Thank you for your contributions.

[yeya24]

This has been resolved along with the change from query priority