Hook up the pipeline schedule mutations to the pipeline schedules Vue form

Summary

As a follow-up from #371987 (closed), the mutations from #372129 (closed) need to be hooked up to allow for the form to create and update pipeline schedules

Scope of work

1. Inject forms properly on new/edit views
2. Hook up the creation logic / add specs
3. Hook up the update logic / add specs
4. Make some changes to the schedule form (some of the variable logic is not needed)