[3.x] Fix physics platform behaviour regression

[lawnjelly]

Lifetime checks for stored RIDs for collision objects assumed they had valid object_ids. It turns out that some are not derived from Object and thus checking ObjectDB returns false for some valid RIDs. To account for this we only perform lifetime checks on valid object_ids.

Fixes #97293 (for 3.x)
3.x version of #97315

Discussion

Although the original MRP in #74732 had valid object ids, it turns out that physics also stores RIDs for objects which are not in ObjectDB. This means we can't lifetime check them with ObjectDB, and the same vulnerability exists for accessing dangling RIDs that caused the original issue.

This should ideally be closed as the current design is unsafe, although there are no reports afaik of this occurring in the wild (although such errors may not result in crash and may only be seen in e.g. asan build).

Making completely safe in this situation is out of scope for this PR, and as stated in the original issue, would involve e.g.

• RID database
• Clearing stored RID references on deletion of objects

[akien-mga]

Thanks!