fix(shorebird_cli): select correct arch for local engine target

[bryanoltman]

Description

Updates availableAndroidArchs to match on exact engine path. This fixes an issue where --target-platform=android-arm64 would incorrectly match android-arm (i.e., arm32) and return the wrong architecture, causing the release command to fail.

Type of Change

• [ ] ✨ New feature (non-breaking change which adds functionality)
• [x] 🛠️ Bug fix (non-breaking change which fixes an issue)
• [ ] ❌ Breaking change (fix or feature that would cause existing functionality to change)
• [ ] 🧹 Code refactor
• [ ] ✅ Build configuration change
• [ ] 📝 Documentation
• [ ] 🗑️ Chore

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 100.00%. Comparing base (ad3be55) to head (43b40d0). Report is 2 commits behind head on main.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #1963 +/- ## ========================================= Coverage 100.00% 100.00% ========================================= Files 177 177 Lines 5560 5560 ========================================= Hits 5560 5560 ``` | [Flag](https://app.codecov.io/gh/shorebirdtech/shorebird/pull/1963/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=shorebirdtech) | Coverage Δ | | |---|---|---| | [shorebird_cli](https://app.codecov.io/gh/shorebirdtech/shorebird/pull/1963/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=shorebirdtech) | `100.00% <100.00%> (ø)` | | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=shorebirdtech#carryforward-flags-in-the-pull-request-comment) to find out more.

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