feat(mnemonic): resume session when persisting to storage

[No-Cash-7970]

For my end-to-end/integration tests, I needed the Mnemonic wallet to behave more like a normal wallet when the mnemonic is persisted to storage.

Changes:

• Resume session with Mnemonic wallet ONLY when mnemonic is persisted to storage
• Remove mnemonic in storage when disconnecting

I'm willing to contribute to the documentation on the Mnemonic wallet. Do you have a repository for the docs?

[drichar]

The GitBook docs are now synced to the use-wallet monorepo, and I would love it if you could flesh out the documentation for the Mnemonic wallet! If you're game, a guide that demonstrates basic e2e/integration testing with it would be huge.

I created the docs using GitBook's app (in the browser), but it's all Markdown as you can see in the new docs folder. When changes are made in the app, a commit is added to the docs/gitbook branch, which can then be periodically merged into main.

If I understand the integration correctly, I can also add commits to the docs/gitbook branch, which will then be propagated to the deployed version. So documentation updates can be made via PR into main, then synced with the GitBook branch.

Really appreciate the ❤️ for the Mnemonic wallet! It'll be so helpful to provide some guidance/examples in the docs.

[drichar]

At first glance your changes here look great. I'll give it a proper review tomorrow and we can get this merged and published once it's approved 👍