Fix TextureStorage not assigning default scale

[Repiteo]

While I don't know the exact conditions to cause it, I've had builds occasionally fail when processing the _render_target_get_sdf_rect functions, citing a value wasn't initalized (default switch case did nothing). The issue was fixed by mirroring the switch implementation in _render_target_allocate_sdf for the two relevant files

[AThousandShips]

I think this should be fixed by ensuring the value is valid, and have an error in the default case as it's not a correct state

[Repiteo]

I would be fine with that route, but I was mirroring the implementation of another function that also handles scale. Would that mean the error case should be applied there as well?

[AThousandShips]

That case doesn't cover all the values though it looks like

Or wait it's a different enum

[AThousandShips]

I think it's more important to identify how an invalid value could have gotten in, that indicates problems, and shouldn't just be patched over

[Repiteo]

It'd be more involved to try and replicate the scenario that caused it, but that's a very valid point. It was happening often (exclusively?) when experimenting with double-precision int structs (godotengine/godot-proposals#7210), so I'll try to work backwards from there

[Repiteo]

Alright, figured it out! I recreated the scenario by making Vector2i use int64_t instead of int32_t and this was the failing output:

D:\Godot\Github\godot\drivers\gles3\storage\texture_storage.cpp(2320) : error C2220: the following warning is treated as an error
D:\Godot\Github\godot\drivers\gles3\storage\texture_storage.cpp(2320) : warning C4701: potentially uninitialized local variable 'scale' used

So line 2320 was the culprit, not strictly because a default case was passed, but because it was using the Vector2i * operator against an int when it was expecting an int64_t. So even though there's an implicit conversion between int32_t and int64_t, this only appears to take effect in a context where int32_t was initialized. Changing "scale" to int64_t fixed the issue, even when uninitalized

So while the proposed change in this PR is technically appropriate, it wasn't actually reaching that stage in practice. Instead, I'll shift direction to your initial proposal and assign an error to the default cases

[akien-mga]

Thanks!