Draft: add support for adding a LaunchActivity to Android expo apps

[Upsilon-Iridani]

Summary

Introduce support for creating a LaunchActivity as outlined in docs/android-chrome-tab-closes-on-background.md

Motivation

Fixes #2245

Testing

• [x] I tested this manually
• [ ] I added automated tests

Documentation

Select one:

• [x] I have added relevant documentation for my changes.
• [ ] This PR does not result in any developer-facing changes.

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[cla-assistant[bot]]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you sign our Contributor License Agreement before we can accept your contribution.
_{You have signed the CLA already but the status is still pending? Let us recheck it.}