Added thirdweb ConnectWallet button to LaunchScreen

[cameronvoell]

Closes #159

Description

This PR adds the ability to connect with accounts from wallet apps via the Thirdweb SDK. The only wallets that were consistently working for me were Rainbow and Metamask so those are the only two options for now.

To Do before removing PR draft state:

• Fix disconnect + re-connect flows for ConnectWallet button
• Add example/.env for reading thirdweb API key
• Update example/README.md

Testing Steps:

1. Follow new example/README.md steps for obtaining a Thirdweb client id (not mandatory, just clears network errors from SDK when it tries to obtain visual assets)
   • See https://github.com/xmtp/xmtp-react-native/blob/cameronvoell/example-wallet-auth/example/README.md#configure-thirdweb-client-api
2. On a device with either Metamask or Rainbow Wallet installed with at least one account, install Example app and click connect button
3. Select either Rainbow or Metamask
4. Should be re-directed to the selected app, click connect when prompted (sometimes takes 5+ seconds)
5. After connecting you should be re-directed back to the Example app. There should be new options to use the connected wallet on either a dev or local network. Select one.
6. You should then be re-directed to Connected wallet app and prompted to sign either an enable account prompt, or first a create account and then enable account prompt.
7. After signing necessary prompts, you should enter the Conversations screen.
8. If you back out of the conversations Screen, your key information should be in the SAVED WALLET, and you can use that to re-enter.
9. You can disconnect the wallet app by clicking on the Connect button while it is connected and then clicking the red exit arrow icon.

Log in flow with Metamask or Rainbow via Thirdweb SDK

Connect Button	Thirdweb Modal	Connect Prompt	Loading indicator

Connected Wallet Button	Sign Prompt

Note on npm install --legacy-peer-deps and @thirdweb-dev/react-native expo dependency version
As mentioned in the linked issue, re-adding the dependency for @thirdweb-dev/react-native means that we need to always run npm install --force when installing dependencies in the example directory (README.md already includes these instructions). The reason is that @thirdweb-dev/react-native specifies a version for expo dependency that is less than our current version. I left a comment on the thirdweb sdk repo to see if updating this dependency has blockers for any reason => thirdweb-dev/js#1778 (comment)
No longer relevant, as thirdweb is compatible with our version of expo now.

[nplasterer]

LGTM. 👍

[github-actions]

🎉 This PR is included in version 1.24.2 🎉

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

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