dillon1000/react

Favor fallthrough switch instead of case statements for work tags (#17648)

* Favor fallthrough switch instead of case statements for work tags

Currently we're inconsistently handling tags that are only relevant
for certain flags. We should throw if the tag is not part of the built
feature flags. This should also mean that the case statements can be
eliminated.

We can achieve this effect by putting the invariant outside of the switch
and always early return in the switch. We already do this in beginWork.
This PR makes this consistent in other places.

* Fail if fundamental/scope tags are discovered without the flag on