Don't use vscroll when fit to content height in TextEdit

[kitbdev]

• fixes https://github.com/godotengine/godot/issues/81764

The horizontal scrollbar part was fixed in https://github.com/godotengine/godot/pull/83286

This makes sure that the vertical scroll bar won't be shown when fit to content height. This fixes the crash mentioned in the issue. https://github.com/godotengine/godot/issues/80546 had a slightly different cause for the crash, which was fixed. This crash only happens at certain sizes depending on the text and is rarer. This fixes it since in _update_wrap_at_column, the v_scroll size is used, which is then removed next time it is updated, causing an infinite loop.