C#: Fix crash due to missing gchandle ref null check
C#: Fix crash due to missing gchandle ref null check

sanikoyes/godot,Paulloz/godot,honix/godot,josempans/godot,vkbsb/godot,okamstudio/godot,Faless/godot,guilhermefelipecgs/godot,Zylann/godot,ZuBsPaCe/godot,groud/godot,sanikoyes/godot,honix/godot,Faless/godot,Zylann/godot,Faless/godot,firefly2442/godot,Valentactive/godot,godotengine/godot,guilhermefelipecgs/godot,okamstudio/godot,BastiaanOlij/godot,guilhermefelipecgs/godot,BastiaanOlij/godot,BastiaanOlij/godot,vkbsb/godot,firefly2442/godot,Shockblast/godot,Paulloz/godot,akien-mga/godot,ex/godot,firefly2442/godot,Shockblast/godot,josempans/godot,Zylann/godot,groud/godot,okamstudio/godot,godotengine/godot,MarianoGnu/godot,Zylann/godot,Valentactive/godot,ZuBsPaCe/godot,Valentactive/godot,DmitriySalnikov/godot,MarianoGnu/godot,pkowal1982/godot,Paulloz/godot,akien-mga/godot,firefly2442/godot,vkbsb/godot,josempans/godot,pkowal1982/godot,ZuBsPaCe/godot,Valentactive/godot,pkowal1982/godot,godotengine/godot,Shockblast/godot,DmitriySalnikov/godot,okamstudio/godot,ZuBsPaCe/godot,josempans/godot,pkowal1982/godot,honix/godot,ZuBsPaCe/godot,Valentactive/godot,groud/godot,Shockblast/godot,ex/godot,pkowal1982/godot,Zylann/godot,honix/godot,ZuBsPaCe/godot,Faless/godot,okamstudio/godot,Zylann/godot,josempans/godot,groud/godot,ZuBsPaCe/godot,josempans/godot,vnen/godot,sanikoyes/godot,sanikoyes/godot,honix/godot,Paulloz/godot,akien-mga/godot,ex/godot,Shockblast/godot,josempans/godot,guilhermefelipecgs/godot,akien-mga/godot,Paulloz/godot,Paulloz/godot,firefly2442/godot,Valentactive/godot,vkbsb/godot,pkowal1982/godot,MarianoGnu/godot,DmitriySalnikov/godot,groud/godot,sanikoyes/godot,sanikoyes/godot,ex/godot,Zylann/godot,DmitriySalnikov/godot,vnen/godot,godotengine/godot,BastiaanOlij/godot,vnen/godot,MarianoGnu/godot,okamstudio/godot,BastiaanOlij/godot,guilhermefelipecgs/godot,godotengine/godot,akien-mga/godot,okamstudio/godot,groud/godot,guilhermefelipecgs/godot,vnen/godot,Zylann/godot,Valentactive/godot,BastiaanOlij/godot,firefly2442/godot,Faless/godot,Paulloz/godot,okamstudio/godot,vkbsb/godot,vkbsb/godot,guilhermefelipecgs/godot,akien-mga/godot,sanikoyes/godot,Valentactive/godot,DmitriySalnikov/godot,godotengine/godot,akien-mga/godot,godotengine/godot,Shockblast/godot,ex/godot,ZuBsPaCe/godot,Faless/godot,vnen/godot,Faless/godot,firefly2442/godot,vkbsb/godot,okamstudio/godot,MarianoGnu/godot,Shockblast/godot,BastiaanOlij/godot,ex/godot,guilhermefelipecgs/godot,Shockblast/godot,Faless/godot,vkbsb/godot,firefly2442/godot,vnen/godot,okamstudio/godot,MarianoGnu/godot,josempans/godot,sanikoyes/godot,ex/godot,DmitriySalnikov/godot,godotengine/godot,pkowal1982/godot,vnen/godot,vnen/godot,akien-mga/godot,DmitriySalnikov/godot,honix/godot,MarianoGnu/godot,MarianoGnu/godot,ex/godot,pkowal1982/godot,BastiaanOlij/godot