fix(app, expo): add missing Firebase imports

[OskarEichler]

What this fixes

• Ensures the Expo config plugin imports Firebase in custom Objective-C AppDelegates that do not import AppDelegate.h.
• Ensures the plugin imports FirebaseCore in custom Swift AppDelegates that do not import Expo.
• Preserves existing import placement for standard templates, newline style, and idempotence.

Without the import, the plugin could add [FIRApp configure] or FirebaseApp.configure() while leaving the generated native source uncompilable.

Implementation

A shared import insertion helper now:

• recognizes an existing exact import;
• inserts after the conventional AppDelegate/Expo anchor when present;
• otherwise inserts before the first import;
• falls back to the start of an import-free file.

Verification

Regression tests reproduce both failures on upstream main and pass with this change. The complete repository gates also pass:

• yarn lerna:prepare
• yarn tests:jest --runInBand — 103 suites, 1,481 tests, 31 snapshots
• yarn tsc:compile
• yarn tsc:compile:consumer
• yarn lint:deps
• yarn reference:api
• yarn compare:types
• focused ESLint
• git diff --check

Compatibility

No public API or breaking changes.

[mikehardy]

Hey @OskarEichler 👋

Thanks for the PR - this looks like a real problem to me. I ran local Jest/unit plus the android/ios/macos e2e suite against it here and it came out clean. Pending CI, then I'll merge.

Cheers

[codecov]

Codecov Report

❌ Patch coverage is 76.92308% with 3 lines in your changes missing coverage. Please review.
✅ Project coverage is 68.49%. Comparing base (81beeca) to head (3f8c5f2).
⚠️ Report is 7 commits behind head on main.

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #9264      +/-   ##
============================================
- Coverage     68.50%   68.49%   -0.01%     
  Complexity     1915     1915              
============================================
  Files           522      522              
  Lines         38116    38125       +9     
  Branches       5189     5191       +2     
============================================
+ Hits          26108    26110       +2     
- Misses        10222    10225       +3     
- Partials       1786     1790       +4     

Flag	Coverage Δ
android-native	63.76% <ø> (ø)
e2e-ts-android	53.94% <ø> (-0.05%)	⬇️
e2e-ts-ios	53.50% <ø> (ø)
e2e-ts-macos	49.67% <ø> (-<0.01%)	⬇️
ios-native	68.78% <ø> (ø)
ios-ruby	100.00% <ø> (ø)
jest	46.29% <76.93%> (+0.03%)	⬆️

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