debug stats get disabled when joining a lobby

[reaperrr]

When opening the skirmish lobby (just an example, I bet MP game lobby and others are affected, too)

• the debug Tick counter breaks (resets and stays at 0)
• the ms/Tick go up by ~3ms and stay there even if you return to main menu

I wonder if the latter is due to the widget not properly releasing/disposing when closed. Fortunately the effect at least doesn't stack, but it's still worth investigating, in my opinion.

[pchote]

A second world is created when the player joins a lobby, and (some of) the perf debug info switches over to this new world instead of staying with the shellmap.

This new world also ticks, and the results from #15222 suggests that this additional tick time is not accounted for in the sleep time calculation used for the FPS limiter. The FPS count (when enabled at 60) starts floating between 56-60 after joining a lobby and returning to the shellmap, vs staying locked at 60 (forced by vsync) with the limiter disabled.

[PunkPun]

It doesn't sem to break? But there is a dip in performance

[pchote]

I can still repro the first point.