fix: improve sms receiver handling

[naveensingh]

Type of change(s)

• Bug fix
• Feature / enhancement
• Infrastructure / tooling (CI, build, deps, tests)
• Documentation

What changed and why

• Added goAsync() call before starting background work.
• Switched to SimpleContactHelper.existsSync() method from feat: add sync method for checking known contacts commons#259 for a faster lookup instead of iterating over all contacts.
• Cleaned up the receiver code and simplified threading logic.
• MmsReceiver needs more changes, both here and in the mmslib for this fix.

Tests performed

Tested receiving and sending SMS

Closes the following issue(s)

• Closes Sometimes no notifications for new received SMS messages #159

Checklist

• I read the contribution guidelines.
• I manually tested my changes on device/emulator (if applicable).
• I updated the "Unreleased" section in CHANGELOG.md (if applicable).
• I have self-reviewed my pull request (no typos, formatting errors, etc.).
• All checks are passing.