ui/sched: always use Dest API

[mastercactapus]

Description: Updates schedule on-call notifications always to use the new dest API.

Which issue(s) this PR fixes: Part of #2639

Describe any introduced user-facing changes: N/A

Describe any introduced API changes: N/A

Additional Info:

• Fixed issue with dest dialogs where incorrect times were recorded when sched. TZ was different than local

[mastercactapus]

Waiting for #3779 to merge

[mastercactapus]

@Forfold It's existing behavior untouched by this work. I agree it should be changed but maybe do that in it's own PR since there may be a bit of refactoring and dialog updates to handle no valid types.

[Forfold]

Gotcha. As long as we don't lose track of it..