Set enable_depth_clip to true by default if SDL_PROP_GPU_DEVICE_CREATE_FEATURE_DEPTH_CLAMPING_BOOLEAN is false

src/gpu/SDL_sysgpu.h

@@ -1096,6 +1096,7 @@ struct SDL_GPUDevice
 
     // Store this for SDL_gpu.c's debug layer
     bool debug_mode;
+    bool default_enable_depth_clip;
     bool validate_feature_depth_clamp_disabled;
     bool validate_feature_indirect_draw_first_instance_disabled;
     bool validate_feature_anisotropy_disabled;