fix: popover ios issue

[abhix4]

What does this PR do?

Issue:

• DatePicker and DateRangePicker not opening at https://app.cal.com/settings/my-account/general timezone.
• #25590 changed the dialog behavior to not being a modal .
• On iOS, the date range picker and single date picker inside a modal dialog stopped opening/working once the popover content was portaled.

Fix:

• Make the popovers modal via <Popover.Root modal> in both the range and single date pickers

• Restore the dialog to its default modal behaviour.

• Fixes #25695

• Fixes CAL-6880

Visual Demo (For contributors especially)

Before:

Mobile:

https://github.com/user-attachments/assets/c644243d-354c-4482-932f-9dfddd7df74c

Desktop:

Screencast from 2025-12-08 17-21-59.webm

After:

Mobile:

https://github.com/user-attachments/assets/cca7d46f-d76b-4773-bca8-9fceb8023f6f

Desktop:

Screencast from 2025-12-08 17-19-28.webm

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.

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[abhix4]

@dhairyashiil added videos for all the mentioned use cases. Please review again when you get time. Thanks

[github-actions[bot]]

E2E results are ready!

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