[SDK-706] Replace deep-link AsyncTask with SDK executors

[franco-zalamena-iterable]

📝 Summary

Moves Iterable deep-link redirect work off the process-wide AsyncTask queue while preserving callback behavior.

🎟️ Jira Ticket: SDK-706

📖 Description

• Replaces the deep-link redirect AsyncTask with an SDK-owned serial executor.
• Resolves redirects and attribution cookies in a focused Kotlin resolver.
• Delivers client callbacks and attribution updates on the main thread, preserving their existing order.
• Adds deterministic, public-flow tests for redirect outcomes, attribution, callback threading, operation ordering, protocol filtering, and handleAppLink behavior.
• Replaces the ignored live-network handleAppLink test with MockWebServer coverage.

This PR is stacked on #1093 (SDK-705).

🧪 How to test?

Passed:

• ./gradlew --no-daemon :iterableapi:testDebugUnitTest :iterableapi-ui:testDebugUnitTest
• ./gradlew --no-daemon :iterableapi:lintDebug :iterableapi:checkstyle :iterableapi-ui:assembleDebug :app:testDebugUnitTest
• Focused deep-link suite: 11 tests, 0 failures

The required standalone inbox-customization sample still fails on its existing Kotlin language-version mismatch: the sample uses Kotlin 1.8 while iterableapi-ui contains Kotlin 1.9 data object declarations.

🧾 Changelog

Updated the existing executor entry to include Iterable deep-link redirects and preserved main-thread callbacks.

📹 Loom recording if applicable

Not applicable.

🐞 Github Issues solved

None.

📚 Docs PR if applicable

Not applicable.

[franco-zalamena-iterable]

Stack review update after the rebase:

• Deep-link redirects use their own dedicated serial lane, separate from push work.
• Success, server-failure, and deterministic read-timeout coverage enforce callback delivery on the main looper and fallback to the original URL.
• A blocked redirect is covered as not delaying push work.
• The existing review discussion is preserved.

Check, BCIT, instrumentation, changelog, Java analysis, and CodeQL passed. I have rerun the unit job after its notification-image and request-ordering failures; the updated top branch passes the affected request tests locally.

Ready for another review.

[franco-zalamena-iterable]

Rerun follow-up: instrumentation remains green, and the unit rerun now fails only on the repository-wide external IterableNotificationTest.testNotificationImage assertion. The earlier request-ordering failure did not recur.

[rtlsilva]

Every 3xx response passes getHeaderField("Location") directly to nullable redirectUrl.
If the header is missing or blank, that violates the failure fallback contract to return the original URL, and handleAppLink then creates no action, so the link is silently not opened.

Suggest treating a missing or blank Location as a failed redirect and return originalUrl, with coverage that also asserts main-thread delivery.