enhancements to shift view in mentor dashboard

Only show shifts if you’re allowed to see them (only show shifts from
released rosters if you’re only allowed to see shifts from released
rosters).

Receive a warning when you cannot see unreleased rosters and there are
terms with unreleased rosters.

Receive a warning when you can view unreleased rosters, you have been
allocated shifts, and there are terms with unreleased rosters.
roster bugfix