[Cashtab] Allow selecting wallet in extension wallet connect

Summary:
T3876

Currently the user has to open extension, select wallet they want, then wallet connect to connect to only that wallet.

With this diff, they can select any wallet, and it will be connected and activated.

Test Plan:
npm test, see screenshot, i tested with the extension, can build it with npm run extension and test on something like blitzchips

Reviewers: #bitcoin_abc, Fabien

Reviewed By: #bitcoin_abc, Fabien

Subscribers: Fabien

Differential Revision: https://reviews.bitcoinabc.org/D18590