Fix UWP build after #17194
Fix UWP build after #17194

`uwp/detect.py` was not setting the `env.msvc` variable to true causing
scons to pass wrong arguments to `msvc` (using `clang/gcc` options)
which in turn break the build due to `-Werror=return-type` not being
recognized by ms compiler.

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