[2.x] perf(tags): prevent loading tag state if loaded previously

[rafaucau]

This PR is similar to #4008, but targets the 2.x branch.
I have not been able to verify if the issue described in #4007 occurs in 2.x, as the Clockwork extension doesn't work with this version, preventing me from observing database queries. Nevertheless, implementing these changes is a precautionary step that can potentially prevent similar issues in the 2.x branch.

Necessity

• Has the problem that is being solved here been clearly explained?
• If applicable, have various options for solving this problem been considered?
• For core PRs, does this need to be in core, or could it be in an extension?
• Are we willing to maintain this for years / potentially forever?

[luceos]

The logic looks sound. I thought the conditional could be simplified, but then we would remove the check for the state actually being null. So 👍 all good.

I would have loved to see the benefit of this on the queries though.