test[DeckPickerContextMenu]: load the backend so the test can run first

[criticalAY]

Note

Assisted-by: Claude Opus 5

Purpose / Description

DeckPickerContextMenuTest does not extend RobolectricTest, so it never calls RustBackendLoader.ensureSetup(). It only passes when some test that does happens to run earlier in the same JVM. When it runs first, every one of its tests dies on:

java.lang.UnsatisfiedLinkError: 'byte[][] net.ankiweb.rsdroid.NativeMethods.openBackend(byte[])'
    at net.ankiweb.rsdroid.Backend.<init>(Backend.kt:86)
    at com.ichi2.anki.CollectionManager.getTR(CollectionManager.kt:188)
    at com.ichi2.anki.dialogs.DeckPickerContextMenu$DeckPickerContextMenuOption.label(DeckPickerContextMenu.kt:98)

Fixes

• Part of [Bug] Unit Tests: java.lang.UnsatisfiedLinkError: 'byte[][] net.ankiweb.rsdroid.NativeMethods.openBackend(byte[])' when mixing RunWith(AndroidJUnit4::class) #14796

How Has This Been Tested?

CI and here:

• ./gradlew :AnkiDroid:testPlayDebugUnitTest --tests "com.ichi2.anki.dialogs.DeckPickerContextMenuTest"

Checklist

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