What does this PR do?

This PR updates the Team Event Type assignment flow to allow adding users who are not yet members of the team. When a non-member email is entered in the “Assignment” tab, the system now treats it as an invitation, adding them to the event type and sending the necessary invites.

Key Changes:

• Updates CheckedTeamSelect component to allow creating new email entries for non-members.
• Adds an (Invite) label next to new emails for better visual feedback.
• Updates the backend to handle invite creation for non-existing users seamlessly.
• Fixes a Prisma error by sanitizing the host object before creation.
• Adds E2E tests to verify assignment invites work as expected.

Fixes #13532 Fixes CAL-3076 /claim #13532

Visual Demo

Video: https://www.loom.com/share/30be5799bca441298264b35b3ccbe8a9

Mandatory Tasks

• I have self-reviewed the code.
• I have updated the developer docs in /docs if this PR makes changes that would require a documentation change. (Or N/A)
• I confirm automated tests are in place that prove my fix is effective or that my feature works.

How should this be tested?

1. Create or navigate to an existing Team.
2. Create or edit a Team Event Type.
3. Go to the Assignment (or Hosts) tab.
4. In the host selection input, type an email address that is not currently a member of the team (e.g., newuser@example.com).
5. Select the email from the dropdown/creation option.
6. Verify that the email appears in the list with an (Invite) label.
7. Save the Event Type.
8. Verify that the user is invited to the team and assigned to the event type.

Checklist

• I have read the contributing guide
• My code follows the style guidelines of this project
• I have commented my code, particularly in hard-to-understand areas
• I have checked if my changes generate no new warnings