Fix: export var type reduce() implemented

[ThakeeNathees]

Fix: #36899

when exporting a var the parser checks if the type is supported and for array and dictionary, they are supported but if they contain any variant which doesn't supported -> BUG!!
setting an unsupported type value and saving the scene will also write invalid text to *.tscn file which will leads to an error Error while parsing *.tscn

## *.tscn file
dictionary = {
0: SubResource( 1 ), ## some value assigned from inspector
1: Object(GDScriptNativeClass,"script":null) ## no value assigned -> writing invalid text
}

fix: validate type recursively (for array and dictionary) to ensure that all types inside are supported.

[akien-mga]

Thanks!

[akien-mga]

Cherry-picked for 3.2.2.