Make the CI build jobs conditional on the static checks' success.

[PapyChacal]

This PR offers to make heavy build jobs conditional on static checks' success.

Rationale: I realized that when I have a minor style issue on my commit, I often correct it right away and push or push-force it. This triggers the jobs as many times as one pushes; even a push force is not cancelling the overridden commit's CI jobs, leading to a fair amount of wasted CI time.

I'm not sure what the stakes are for the Godot team, be it quotas and/or bills, but I guess it wouldn't hurt to avoid wasting it. If this is of interest, I can do the same on Godot's side, where it would be more significant.

[PapyChacal]

Used reusable workflow instead, so this just works now. I did some renaming so reads better in the Actions tab, and for consistency between SCons and CMake builds.

For the engine's main repository, it turns out someone already did the work: https://github.com/godotengine/godot/pull/65232