TileMap: Fix infinite loop when trying to bucket-delete empty tiles.
TileMap: Fix infinite loop when trying to bucket-delete empty tiles.

Right-clicking when the bucket tool is enabled means "erase all instances of this tile".
So it doesn't make sense to try doing this for empty tiles :P

Fixes #10065

mcanders/godot,Faless/godot,groud/godot,n-pigeon/godot,vnen/godot,jejung/godot,Zylann/godot,BastiaanOlij/godot,sanikoyes/godot,tomreyn/godot,ZuBsPaCe/godot,zicklag/godot,vnen/godot,okamstudio/godot,Valentactive/godot,firefly2442/godot,akien-mga/godot,godotengine/godot,BastiaanOlij/godot,ZuBsPaCe/godot,NateWardawg/godot,firefly2442/godot,Faless/godot,akien-mga/godot,vnen/godot,godotengine/godot,RandomShaper/godot,Faless/godot,ageazrael/godot,RandomShaper/godot,akien-mga/godot,BastiaanOlij/godot,MarianoGnu/godot,firefly2442/godot,ageazrael/godot,NateWardawg/godot,vkbsb/godot,mcanders/godot,okamstudio/godot,DmitriySalnikov/godot,akien-mga/godot,groud/godot,tomreyn/godot,groud/godot,mcanders/godot,Paulloz/godot,tomreyn/godot,akien-mga/godot,DmitriySalnikov/godot,pkowal1982/godot,RandomShaper/godot,ZuBsPaCe/godot,zicklag/godot,n-pigeon/godot,ageazrael/godot,FateAce/godot,MarianoGnu/godot,DmitriySalnikov/godot,firefly2442/godot,ZuBsPaCe/godot,RandomShaper/godot,Valentactive/godot,ZuBsPaCe/godot,Valentactive/godot,vkbsb/godot,ageazrael/godot,guilhermefelipecgs/godot,Zylann/godot,jejung/godot,ageazrael/godot,MarianoGnu/godot,sanikoyes/godot,Valentactive/godot,Shockblast/godot,Zylann/godot,jejung/godot,BastiaanOlij/godot,sanikoyes/godot,guilhermefelipecgs/godot,Faless/godot,Brickcaster/godot,Faless/godot,guilhermefelipecgs/godot,tomreyn/godot,akien-mga/godot,MarianoGnu/godot,vkbsb/godot,n-pigeon/godot,NateWardawg/godot,mcanders/godot,groud/godot,MarianoGnu/godot,okamstudio/godot,ex/godot,Zylann/godot,akien-mga/godot,NateWardawg/godot,mcanders/godot,RandomShaper/godot,Zylann/godot,pkowal1982/godot,ageazrael/godot,Paulloz/godot,vkbsb/godot,akien-mga/godot,jejung/godot,godotengine/godot,honix/godot,godotengine/godot,BastiaanOlij/godot,guilhermefelipecgs/godot,okamstudio/godot,MarianoGnu/godot,jejung/godot,Faless/godot,Valentactive/godot,josempans/godot,firefly2442/godot,DmitriySalnikov/godot,n-pigeon/godot,Shockblast/godot,josempans/godot,Zylann/godot,vnen/godot,ZuBsPaCe/godot,zicklag/godot,MarianoGnu/godot,ex/godot,NateWardawg/godot,RandomShaper/godot,BastiaanOlij/godot,guilhermefelipecgs/godot,vkbsb/godot,vkbsb/godot,zicklag/godot,Zylann/godot,honix/godot,tomreyn/godot,n-pigeon/godot,pkowal1982/godot,okamstudio/godot,Paulloz/godot,n-pigeon/godot,Shockblast/godot,zicklag/godot,Valentactive/godot,FateAce/godot,honix/godot,Brickcaster/godot,honix/godot,Paulloz/godot,Brickcaster/godot,ex/godot,guilhermefelipecgs/godot,ex/godot,ex/godot,okamstudio/godot,ex/godot,okamstudio/godot,groud/godot,pkowal1982/godot,DmitriySalnikov/godot,pkowal1982/godot,NateWardawg/godot,pkowal1982/godot,Faless/godot,vnen/godot,groud/godot,vnen/godot,firefly2442/godot,okamstudio/godot,sanikoyes/godot,sanikoyes/godot,BastiaanOlij/godot,josempans/godot,FateAce/godot,vnen/godot,ageazrael/godot,josempans/godot,FateAce/godot,vnen/godot,godotengine/godot,NateWardawg/godot,josempans/godot,sanikoyes/godot,FateAce/godot,sanikoyes/godot,pkowal1982/godot,Shockblast/godot,firefly2442/godot,n-pigeon/godot,FateAce/godot,ZuBsPaCe/godot,ex/godot,NateWardawg/godot,Valentactive/godot,josempans/godot,Paulloz/godot,BastiaanOlij/godot,guilhermefelipecgs/godot,Brickcaster/godot,zicklag/godot,vkbsb/godot,Brickcaster/godot,sanikoyes/godot,ZuBsPaCe/godot,honix/godot,Paulloz/godot,DmitriySalnikov/godot,Zylann/godot,godotengine/godot,Brickcaster/godot,guilhermefelipecgs/godot,okamstudio/godot,Valentactive/godot,Shockblast/godot,Brickcaster/godot,Paulloz/godot,godotengine/godot,MarianoGnu/godot,jejung/godot,Shockblast/godot,Shockblast/godot,Faless/godot,RandomShaper/godot,honix/godot,firefly2442/godot,ex/godot,pkowal1982/godot,vkbsb/godot,josempans/godot,josempans/godot,mcanders/godot,okamstudio/godot,Shockblast/godot,DmitriySalnikov/godot,godotengine/godot,NateWardawg/godot