[Multiplayer] Fix crash in spawner get_spawnable_scene.
[Multiplayer] Fix crash in spawner get_spawnable_scene.

godotengine/godot,sanikoyes/godot,josempans/godot,guilhermefelipecgs/godot,BastiaanOlij/godot,sanikoyes/godot,guilhermefelipecgs/godot,sanikoyes/godot,Shockblast/godot,vkbsb/godot,vkbsb/godot,josempans/godot,BastiaanOlij/godot,Shockblast/godot,josempans/godot,BastiaanOlij/godot,sanikoyes/godot,Shockblast/godot,BastiaanOlij/godot,Shockblast/godot,guilhermefelipecgs/godot,sanikoyes/godot,guilhermefelipecgs/godot,Shockblast/godot,pkowal1982/godot,godotengine/godot,BastiaanOlij/godot,pkowal1982/godot,pkowal1982/godot,godotengine/godot,godotengine/godot,BastiaanOlij/godot,godotengine/godot,BastiaanOlij/godot,josempans/godot,guilhermefelipecgs/godot,godotengine/godot,vkbsb/godot,godotengine/godot,sanikoyes/godot,sanikoyes/godot,vkbsb/godot,vkbsb/godot,vkbsb/godot,pkowal1982/godot,BastiaanOlij/godot,josempans/godot,guilhermefelipecgs/godot,pkowal1982/godot,Shockblast/godot,Shockblast/godot,pkowal1982/godot,pkowal1982/godot,guilhermefelipecgs/godot,vkbsb/godot,josempans/godot,pkowal1982/godot,Shockblast/godot,josempans/godot,godotengine/godot,sanikoyes/godot,josempans/godot,vkbsb/godot,guilhermefelipecgs/godot