Fix EntityWidgetConfigure build

[TimoPtr]

Summary

We've merged #7007 but it was not up to date on main and we end up into a build that is not building because of that. This Pr fix this by simply using the new methods available in the use case.

Checklist

• New or updated tests have been added to cover the changes following the testing guidelines.
• The code follows the project's code style and best_practices.
• The changes have been thoroughly tested, and edge cases have been considered.
• Changes are backward compatible whenever feasible. Any breaking changes are documented in the changelog for users and/or in the code for developers depending on the relevance.
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[Copilot]

Pull request overview

This PR updates the Entity Widget configuration flow to match the updated GetEntitiesForDisplayUseCase API (post-#7007), unblocking compilation by switching call sites and tests to the new snapshot(...) method and the updated EntityDisplayItem construction.

Changes:

• Update EntityWidgetConfigureViewModel to use getEntitiesForDisplay.snapshot(serverId) instead of the previous call form.
• Update unit/UI tests and preview state to construct EntityDisplayItem via EntityDisplayItem(entity) (instead of the removed .from(...)).
• Adjust ViewModel tests to mock getEntitiesForDisplay.snapshot(...).

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 1 comment.

File	Description
app/src/test/kotlin/io/homeassistant/companion/android/widgets/entity/EntityWidgetConfigureViewModelTest.kt	Updates mocks/helpers to use snapshot(...) and EntityDisplayItem(entity) construction.
app/src/test/kotlin/io/homeassistant/companion/android/widgets/entity/EntityWidgetConfigureScreenTest.kt	Updates test state to use EntityDisplayItem(ENTITY) instead of EntityDisplayItem.from(...).
app/src/main/kotlin/io/homeassistant/companion/android/widgets/entity/EntityWidgetConfigureViewModel.kt	Switches entity loading to getEntitiesForDisplay.snapshot(serverId).
app/src/main/kotlin/io/homeassistant/companion/android/widgets/entity/EntityWidgetConfigureScreen.kt	Updates preview state to use the new EntityDisplayItem(previewEntity1) constructor.