Fix for EMCC_USE_NINJA + embuilder --force. NFC (#19181)

Since --force set `do_clear` we cannot use that as a sign not do run
the build.

Author: sbc100

embuilder.py

@@ -268,7 +268,7 @@ def main():
     time_taken = time.time() - start_time
     logger.info('...success. Took %s(%.2fs)' % (('%02d:%02d mins ' % (time_taken // 60, time_taken % 60) if time_taken >= 60 else ''), time_taken))
 
-  if USE_NINJA and not do_clear:
+  if USE_NINJA and args.operation != 'clear':
     system_libs.build_deferred()
 
   if len(tasks) > 1 or USE_NINJA: