fix(schedules): handle availability spillover on date overrides

[abhijeetsingh-22]

What does this PR do?

This PR fixes an issue where availability ranges spilling over from the previous day were incorrectly persisting even when the next day had a specific "Date Override"

• Fixes Date override is not functioning as expected #26804
• Fixes CAL-7063

Visual Demo

Video Demo:

When a user has a schedule spanning midnight (e.g., Tue 9 PM - Wed 3 AM) and sets a specific Date Override for the next day (Wednesday), the system was incorrectly showing them as available from midnight to 3 AM. This happened because the Tuesday's availability "spilled over" into Wednesday

Availability settings:

Before

• There are slots available on 28th and 31st but this is incorrect as these days are marked as unavailable via date overrides

before.mp4

After

• The days with override ( 28th, 29th and 31st ) are correctly marked as unavailable

after.mp4

After

Image Demo :

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. 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?

• Configure availability Hours: Set Availability to span across midnight (e.g. 9:00 PM to 3:00 AM).
• Apply this to all weekdays (Mon-Fri).
• Add Date Override: Pick a specific date (e.g., coming Wednesday) and mark it as Unavailable.
• Verify Booking Page:
  • Go to the public booking page.
  • Check the overridden date.
  • Expected: The day should be completely unavailable.
  • Before Fix: You would see slots from 00:00 to 03:00 (spillover from Tuesday night).

Checklist

[cubic-dev-ai]

No issues found across 2 files