fix(messaging): serialize array data values as JSON

[OskarEichler]

What changed

• Serialize array-valued outgoing RemoteMessage.data entries with JSON, consistently with other object values.
• Add a focused regression test with nested objects.

Observable behavior correction

• Arrays now retain their JSON structure. For example, [{ id: 1 }] becomes [{"id":1}] instead of [object Object].
• This changes only the malformed wire value produced for array data. String, primitive, plain-object, and null serialization retain their existing behavior; there is no public API or type change.

Why

The public RemoteMessage.data value type accepts objects, and the serializer already JSON-encodes objects. Its explicit array exclusion routed arrays through JavaScript string coercion instead, losing quoting and nested object data before Android's native RemoteMessage.Builder received it.

Verification

• Exact baseline regression: expected [{"id":1},{"id":2}], received [object Object],[object Object].
• Focused Messaging Jest: 33 passing.
• Full Jest: 103 suites, 1,480 tests, 31 snapshots.
• Android App + Messaging E2E: 86 passing, 6 pending.
• Android unit and post-E2E coverage processing pass.
• lerna:prepare, JS lint, dependency-cruiser, both TypeScript compiles, API-reference generation, type-parity comparison, and git diff --check pass.

[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

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 68.20%. Comparing base (0470b71) to head (3dcd282).
⚠️ Report is 4 commits behind head on main.

Additional details and impacted files

@@              Coverage Diff              @@
##               main    #9253       +/-   ##
=============================================
+ Coverage     47.23%   68.20%   +20.98%     
- Complexity        0     2096     +2096     
=============================================
  Files           248      441      +193     
  Lines         11603    25163    +13560     
  Branches       2494     4256     +1762     
=============================================
+ Hits           5479    17161    +11682     
- Misses         5303     6612     +1309     
- Partials        821     1390      +569     

Flag	Coverage Δ
android-native	65.06% <ø> (?)
e2e-ts-android	54.09% <100.00%> (?)
e2e-ts-macos	49.88% <0.00%> (?)
jest	47.34% <0.00%> (+0.12%)	⬆️

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