Fix tests failing with cargo test but not with cargo nextest

[Wumpf]

Related

• Fixes unit test of re_view_spatial fail at main branch (commit: f101cbd) #12011

What

The difference between those two is whether each test gets its own process. So it was clear that we're leaking state. Turns out it's about store subscribers which often rely on unique store ids for distinguishing concrete stores.

Solving this on the store subscriber level with the current arch is hard because the subscriber correctly accumulate data from all parallel running tests that do writes do stores with the exact same id

[github-actions]

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Result	Commit	Link	Manifest
✅	a7f7451	https://rerun.io/viewer/pr/12061	+nightly +main

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