docs: Update README.md with new expo instructions

[andrepimenta]

Description

Adding new instructions for Expo:

For internal developers

• Access Runway via Okta and go to the Expo bucket either on the iOS or Android section. From there you will see the available development builds (android-expo-dev-build.apk or ios-expo-dev-build.ipa).
• For Android:
  • Install the .apk on your Android device or simulator.
• For iOS:
  • Device: you need to have your iPhone registered with our Apple dev account. If you have it, you can install the .ipa on your device.
  • Simulator: please follow the native development section and run yarn setup and yarn start:ios as the .ipa will not work for now, we are working on having an .app that works on simulators.

[SOON] For external developers (we are testing the new dev builds and will make them publicly available soon after)

Related issues

Fixes:

Manual testing steps

1. Go to this page...

Screenshots/Recordings

Before

After

Pre-merge author checklist

• I’ve followed MetaMask Contributor Docs and MetaMask Mobile Coding Standards.
• I've completed the PR template to the best of my ability
• I’ve included tests if applicable
• I’ve documented my code using JSDoc format if applicable
• I’ve applied the right labels on the PR (see labeling guidelines). Not required for external contributors.

Pre-merge reviewer checklist

• I've manually tested the PR (e.g. pull and build branch, run the app, test code being changed).
• I confirm that this PR addresses all acceptance criteria described in the ticket it closes and includes the necessary testing evidence such as recordings and or screenshots.

[sethkfman]

LGTM

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud