Allow users to disable reading and returning observability information in the console

This issue tracks providing a mechanism for users to disable and turn off stats collection in the console. The console can (indirectly) issue expensive queries against the database when polling and fetching observability information that can cause instability to the console itself. Cluster resources are consumed for running these queries as well and in some cases, be also negatively impacted. Expensive queries impact the console more frequently for larger workloads running on CRDB.

We should allow disabling stats for the following pages where we have seen stability issues:

1. Databases page
2. SQL Activity pages for persisted statistics

We should also explore disabling the automatic polling behavior of the console and allow users to **manually** "refresh" or "fetch" various information to avoid indirectly issuing these expensive queries - there are RU consumption implications here as well.

Note this is a short-term solution until we can optimize and tune the process of returning observability information to the console. We have several tracking improvements (e.g., virtual indexes, obs service, pagination, etc.).

Jira issue: CRDB-22518