* refactor: replace loggedInUsersTz with timeZone in busy-times API
- Add new timeZone parameter to CalendarBusyTimesInput
- Mark loggedInUsersTz as deprecated
- Update getBusyTimes endpoint to prioritize timeZone parameter
- Maintain backward compatibility with loggedInUsersTz
- Add validation to ensure at least one timezone parameter is provided
- Update API documentation with new parameter example
Fixes#25423
* fix: improve timezone validation in CalendarBusyTimesInput
- Use custom ValidatorConstraint instead of problematic ValidateIf
- Properly validate that at least one timezone parameter is provided
- Improve code quality and clarity
* fix: update DTOs for getBusyTimes
* cleanup
* fix: abstract normalize timezone logic into platform types util function
* chore: update e2e tests
* fixup
* fixup
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Co-authored-by: Ryukemeister <sahalrajiv6900@gmail.com>
Co-authored-by: Rajiv Sahal <sahalrajiv-extc@atharvacoe.ac.in>
