[Save] Use Save action from View Modified dialog

Use the Save action from the View Modified
dialog, instead of partially replicating
its behavior. This should resolve
nasa/mct#243, as the Save action correctly
considers those cases, and additionally
should reduce the likelihood of similar
issues arising in the future.
[Save] Amend unit tests for view modified dialogs

Amend units tests for view modified dialogs
to match pre-conditions and options available
for consolidated view modified dialog.