What does this PR do?

This PR fixes a bug where users could not delete the first time slot in their availability schedule or date overrides. Previously, only slots 2 and onwards showed a trash icon; the first slot only had the "+" button.

Changes:

• Show the trash (delete) button on all time slots when there are 2 or more slots, including the first one.

• When there is only 1 slot, no trash button is shown (you must keep at least one slot).

• Fixes Calendar override remove first time #26448

• Fixes CAL-XXXX (Linear issue number - should be visible at the bottom of the GitHub issue description)

Visual Demo (For contributors especially)

A visual demonstration is strongly recommended, for both the original and new change (video / image - any one).

Video Demo (if applicable):

Image Demo (if applicable):

• Add side-by-side screenshots of the original and updated change.
• Highlight any significant change(s).

Mandatory Tasks (DO NOT REMOVE)

• I have self-reviewed the code (A decent size PR without self-review might be rejected).
• I have updated the developer docs in /docs if this PR makes changes that would require a documentation change. If N/A, write N/A here and check the checkbox.
• I confirm automated tests are in place that prove my fix is effective or that my feature works.

How should this be tested?

1. Go to Settings → Availability (or /availability).
2. Open any schedule.
3. For any day, add 2 or 3 time slots using the "+" button.
4. Check: All slots (including the first) should show a trash icon.
5. Click trash on the first slot – it should be removed.
6. When only 1 slot is left, the trash icon should disappear (you cannot delete the last slot).

• Are there environment variables that should be set?
• What are the minimal test data to have?
• What is expected (happy path) to have (input and output)?
• Any other important info that could help to test that PR

Checklist