Scheduler - Migrate popup recurrence and form customization tests to isolated environment

[bit-byte0]

What

Migrated popup form tests from full Scheduler to isolated createAppointmentPopup() helper

How

Replaced createScheduler() + showAppointmentPopup() with createAppointmentPopup() directly, using the POM to interact with the form. Removed duplicate tests, applied it.each where applicable

[Copilot]

Pull request overview

This PR migrates Scheduler appointment popup recurrence and form customization tests from the full dxScheduler integration setup to an isolated createAppointmentPopup() test environment, reducing dependency on Scheduler rendering and improving test focus.

Changes:

• Added isolated AppointmentPopup tests covering validation behavior, recurrence form state/UX, localization, and form items customization.
• Removed corresponding validation/recurrence/customization test coverage from the Scheduler integration test suite to avoid duplication.
• Kept Scheduler integration tests for behaviors that require Scheduler interactions (e.g., popup opening via UI interactions, toolbar behaviors, popup sizing options).

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 3 comments.

File	Description
packages/devextreme/js/__internal/scheduler/appointment_popup/appointment_popup.test.ts	Adds/extends isolated AppointmentPopup tests for validation, recurrence form, localization, animation offset, and form item customization.
packages/devextreme/js/__internal/scheduler/appointment_popup/appointment_popup.integration.test.ts	Removes tests migrated to isolated environment and keeps Scheduler-dependent integration scenarios.

[Copilot]

Pull request overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.