Code clean up for ServerMetrics and BrokerMetrics

As part of https://github.com/apache/pinot/pull/10171 and https://github.com/apache/pinot/issues/9055 on query killing we have added registration point of metrics to BrokerMetrics and ServerMetrics, so that we don't pass down the actual metric instance to accountant code. Now we can do the refactoring for other parts of the code similarly.

Start by reviewing pull request 10171 and issue 9055, then trace the registration points in ServerMetrics and BrokerMetrics. Identify the other accountant-related paths that still pass metric instances directly. Done means those paths follow the same registration approach, with the relevant existing tests passing.

Written by the indexing model from the issue text.