Calendar: Add an Unassigned Shift

[elizabethfoster02]

link to PR: https://github.com/elizabethfoster02/casa-myrna/pull/155

Purpose We want to be able to add a shift that has not been assigned to an employee from the Add Shift modal

TODO

• [x] Claim this ticket by adding your name and moving to "In Progress"
• [x] Get updated with the codebase
  • [x] git checkout dev
  • [x] git pull
  • [x] THEN create a new branch as per usual
  • [x] npm install (this updates your dependencies)
  • [x] npm run dev
• [x] Implement description above
• [x] Create a PR for this ticket
• [x] Move this ticket into "Ready for Review"

Testing

• [x] Desktop