Add source or sub model quality metric for when hTab starting elevations are below XS invert

[sclaw]

RAS raises a warning that blocks model completion when hTab starting elevations are below XS invert. This typically occurs on execution of a newly created sub model. There should be a model quality metric to warn users that the model will hang and the job will need to be revoked. Alternatively, an option should be found to set hTab prior to model execution.