Missing MoltenVK for iOS build step

[raminf]

Was following installations steps to build libgodot for iOS on an M3 Mac running Sonoma 14.5. Kept getting "MoltenVK SDK installation directory not found" error. Went down the rabbit hole of getting and building MoltenVK SDK from source. Turned out there was an easier way: an official Mac binary installer from https://vulkan.lunarg.com/sdk/home. It defaults to installing in the Home directory (which is where the libgodot build scripts looks for).

Once done, ./build_libgodot.sh --target ios works. After that, the iosTest demo can build and install in XCode.

Hope this helps someone. May be good to add it to the instructions.

[kisg]

Thanks for the report, we will add it to the instructions.