test: add calculator widget device tests

[ovitrif]

Related: #950

Stacked on #943.

Description

• Adds calculator widget device UI coverage rebuilt on top of feat: calculator v61 redesign #942.
• Covers BTC input to fiat conversion and fiat input to BTC conversion.
• Leaves calculator unit coverage in feat: calculator v61 redesign #942, where the view model and formatting/number-pad logic tests were added.
• Verifies persisted calculator widget state using deterministic USD rate, store state, and locale setup.
• Uses the DeviceIntegration lane from test: add android test lanes #943 and adds the DeviceUiIntegration lane for calculator device UI coverage.
• Removes the stale OS-widget updater dependency now that feat: calculator v61 redesign #942 keeps the calculator OS widget out of scope.

Preview

N/A

QA Notes

Manual Tests

N/A

Automated Checks

• Local: ./gradlew compileDevDebugKotlin testDevDebugUnitTest compileDevDebugAndroidTestKotlin detekt
• Local dry run: ./gradlew connectedDevDebugDeviceUiIntegrationAndroidTest -m
• Device run before the annotation rename: ./gradlew connectedDevDebugDeviceUiIntegrationAndroidTest ran 2 tests on Pixel 10 Pro - 16.

[chatgpt-codex-connector]

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