Prevent splash screens from being closeable

Removed the WindowShouldClose() check from the splash screen loop
to prevent users from closing the splash screens prematurely.

Previously, users could press ESC or click the X button during
splash screens, which would skip to the game but create confusion
since it didn't actually exit the application. Now splash screens
play through completely for a consistent user experience.

Developers can still skip splashes using the --no-logo flag.

src/main.c

@@ -142,7 +142,7 @@ int main( int argn, const char** argc ) {
 			splashInit();
 			bool splashDone = false;
 			
-			while ( !splashDone && !WindowShouldClose() ) {
+			while ( !splashDone ) {
 				float delta = GetFrameTime();
 				splashDone = splashUpdate( delta );
 				splashDraw();