build: publish mobile beta 1.9.0-beta.3

[Priveetee]

Summary

• Prepare Android beta 1.9.0-beta.3 with version code 10826.
• Send the UnifiedPush Web Push p256dh and auth keys with device registration so the server can encrypt notification payloads for Sunup.

Verification

• :app:testDebugUnitTest, :app:lintDebug, :app:assembleDebug, and :app:assembleRelease passed locally.
• Android CI passed for the encryption-key change.
• TypeType-Server tests, OpenAPI validation, Docker image build, and beta image dispatch passed on the current dev changes.

Device check

• End-to-end notification receipt has not yet been verified with this APK. Please verify after the beta is published.