Scheduler - Migrate popup resources and save/cancel tests to isolated environment

[bit-byte0]

What

Migrate 15 tests from integration to isolated createAppointmentPopup() helper (Form + Popup only, no full Scheduler)

How

Groups: Resources (6), Icons (2), Save/Cancel (7).
No production code changes, only test helper gets resources option.

[Copilot]

Pull request overview

This PR migrates several Scheduler Appointment Popup resource-related checks and save/cancel behavior tests from the integration suite into the isolated AppointmentPopup test environment, reducing reliance on full Scheduler integration for popup-specific behavior.

Changes:

• Added isolated-environment tests covering resource group structure, resource editor widget types, FontAwesome resource icons, and subject icon color updates.
• Moved save/cancel behavior assertions into isolated tests by validating onSave callback behavior for common and recurring appointments.
• Extended the AppointmentPopup test factory to accept Scheduler-like resources configuration and preload resource data when provided; removed the migrated tests (and now-unused types) from the integration suite.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
packages/devextreme/js/__internal/scheduler/appointment_popup/appointment_popup.test.ts	Adds isolated AppointmentPopup tests for resources, icons, and save/cancel behavior.
packages/devextreme/js/__internal/scheduler/appointment_popup/appointment_popup.integration.test.ts	Removes resource and save/cancel tests that were migrated to the isolated suite and drops an unused type import.
packages/devextreme/js/__internal/scheduler/tests/mock/create_appointment_popup.ts	Extends the isolated popup factory to accept resources and preload them before showing the popup.