Support stretch ratio in GridContainer

[KoBeWi]

https://github.com/godotengine/godot-proposals/issues/97#issuecomment-2095080729 idk if it's a bugfix or enhancement.

https://github.com/godotengine/godot/assets/2223172/261ca4d5-d545-4111-be8a-eb78d8035740

[kitbdev]

Found some issues.

When the first row stretch ratio is less than one and the second row does not stretch, the second row moves far away, outside of the Container:

Changing the stretch ratio makes it jitter and not fit into the container: When there is a minimum size and both stretch it can overlap (shown after the above):

[KoBeWi]

idk how to fix it :/