serverutils: consider granting all tenant capabilities by default

#109449 adds overrides to existing cluster settings that gate some functionality in the virtual clusters to be enabled by default. The rationale is that that we have more tests that want this than those that need precise control of what's enabled.

We should also consider simply granting all tenant capabilities by default too (unless the caller explicitly asks not to). We do need to be mindful that waiting for capabilities can have non-trivial overhead which can slowdown the CI pipeline (but perhaps 132211f7d7eb310ecdcb69a12a36c6a5cc0a2311 made it quick enough).

Jira issue: CRDB-30943