multitenant: Remove dropdown from DB Console when on a non-UA cluster

[amruss]

See: https://cockroachlabs.slack.com/archives/C05VAJ5H3QS/p1699495881149839?thread_ts=1699471492.039549&cid=C05VAJ5H3QS

We have a bug where for single-tenant clusters, they see a tenant dropdown menu in the UI. This should not happen.

Jira issue: CRDB-33377

[blathers-crl[bot]]

Hi @dhartunian, please add branch-* labels to identify which branch(es) this release-blocker affects.

_{:owl: Hoot! I am a Blathers, a bot for CockroachDB. My owner is dev-inf.}

[dhartunian]

I cannot reproduce this on latest release-23.2 branch using a secure cluster and start-single-node.

[amruss]

Reopening, this is popping back up again: https://cockroachlabs.slack.com/archives/C063CP41TG9/p1701450260389879

[amruss]

We're also leaking in the SQL shell:

[dhartunian]

@amruss do you have a reproduction for this issue? I'm still unable to create a repro on my end. Starting a blank cluster does not show the tenant dropdown, nor does it leak the system tenant in the SQL shell. I've tried to play around with my cookie settings to force it to show up when it shouldn't and I can't do that either. If there's a roachprod cluster where this is happening or on some other test cluster, just point me to it and I can try to track it down.

[celiala]

removing GA-blocker label as well (as per Slack thread: https://cockroachlabs.slack.com/archives/C063CP41TG9/p1702699835346909?thread_ts=1702681134.189089&cid=C063CP41TG9)

[dhartunian]

@amruss is it possible this ticket is regarding the tenant dropdown on the metrics page? I realized the discussion never clarifies what actual UI element is the problem.

Also, if there's a change necessary in the SQL shell, can you file a separate ticket and route to SQL team?