chore(cameras): move if check out of _validate functions

tests/cameras/test_realsense.py

@@ -154,7 +154,9 @@ def test_async_read_timeout(mock_enable_device):
 
     try:
         with pytest.raises(TimeoutError):
-            camera.async_read(timeout_ms=0)
+            camera.async_read(
+                timeout_ms=0
+            )  # NOTE(Steven): This is flaky as sdometimes we actually get a frame
     finally:
         if camera.is_connected:
             camera.disconnect()