Propagation type changes must be done as a separate call, in the
same way as read only bind mounts.
To fix this:
1. Ensure propagation type change flags aren't included in other calls.
2. Apply propagation type change in a separate call.
Also:
* Make it clear which parameters are ignored by passing them as empty.
* Add tests to ensure Mount options are applied correctly.
Fixes#30415
Signed-off-by: Steven Hartland <steven.hartland@multiplay.co.uk>
