[Android Web] "Mobile Wallet Adapter" option in wallet selection model does nothing

[Funkatronics]

Describe the bug
The wallet selection modal button(s) that many sites are using from wallet-adapter are not functioning properly with Mobile Wallet Adapter. The wallet connection buttons present a wallet selection modal on both desktop and mobile that ask the user to select the wallet they wish to connect with. On Android browsers, Mobile Wallet Adapter is presented as an option in this list. Tapping on the "Mobile Wallet Adapter" option does nothing (though there is a workaround to make it work, see below).

At the time of writing, this issue can be observed on the following websites:

• solarplex.xyz
• tiexo.com

To Reproduce
Steps to reproduce the behavior:

1. On an android device or emulator with at least one wallet application installed, open https://solana-labs.github.io/wallet-adapter/example/ in Chrome (or another chromium based browser that is known to work with Mobile Wallet Adapter, ie Edge)
2. Click on one of the "Select Wallet" buttons in the "Dialog/Modal Button" section. A modal will open asking you to choose the wallet to connect to
3. Tap on the "Mobile Wallet Adapter" option
4. See that nothing happens. reaping these steps will produce the same, noting happens.

Known Workaround
Steps to workaround this behavior and trigger a :

1. Click on one of the "Select Wallet" buttons in the "Dialog/Modal Button" section. A modal will open asking you to choose the wallet to connect to
2. tap on the "Burner Wallet" option, or any other option available other than "Mobile Wallet Adapter"
3. Click again on one of the "Select Wallet" buttons in the "Dialog/Modal Button" section. A modal will open asking you to choose the wallet to connect to
4. This time tap on the "Mobile Wallet Adapter" option
5. The android disambiguation dialog should now open asking you to select an installed wallet. Selecting a wallet and continuing with the MWA flow should work as expected.

Expected behavior
If the wallet selection dialog is presented on Android, tapping on the "Mobile Wallet Adapter" option should immediately launch the association url and show the wallet disambiguation dialog or open the users installed wallet app. The user should not need to select a different wallet first, then go back to MWA to get it to work.

Desktop (please complete the following information):

• OS: Android
• Browser Chrome, Edge
• Version Latest/all

Smartphone (please complete the following information):

• Device: Any Android, tested on Saga, Pixel 3a, and several emulators
• OS: tested on Android 29, 30, 31, presumably all android versions are impacted (android version does not have impact here)
• Browser Chrome, Edge, presumably all android browsers that should support MWA

Additional context
Alternatively, dApps should try using the "Multi Button" options provided in our UI libs. The Multi Button options on the example site work as expected on desktop and mobile: on desktop the present the wallet seclectionmodal, and on mobile when MWA is supported, the wallet selection modal is not shown and the MWA association url is launched correctly instead. This is the recommended UX for both desktop and mobile so these "WalletMultiButton"s should probably be used instead of the modal buttons.