Add account switcher component in the Accounts webview tab

[pkukielka]

Changes

That PR:

1. Fixes webview crashes when switching accounts with Account tab open
2. Add Switch Account button on the Accounts tab when accountSwitchingInWebview capability is enabled in client.

Test plan

Testing with jetbrains main:

Fixes https://linear.app/sourcegraph/issue/QA-150

1. Open Accounts tab
2. Click Cody icon, then Manage Accounts
3. Switch the account
4. Account tab should re-render properly (after a 1-2s delay) showing new account details

Testing with jetbrains migrated to webview account management:

Account switching:

1. Open Accounts tab
2. Click Switch Account
3. Select account you want to switch to from the list
4. Account tab should re-render properly (after a 1-2s delay) showing new account details

Signing out:

1. Open Accounts tab
2. Click Sign Out
3. You should be moved to the Sign In panel

Account adding:

1. Open Accounts tab
2. Click 'Switch Account', and then 'Add another account'
3. Type url of your endpoint
4. You should be redirected to the web page to confirm adding the token
5. Account should be added and displayed as active

Note: If wrong endpoint is provided web redirection will fail, but no error is displayed in the UI.
This definitely can be improved.

Account adding with token:

1. Open Accounts tab
2. Click 'Switch Account', and then 'Add another account'
3. Type url of your endpoint
4. Click 'Access Token (optional)'
5. Type incorrect access token and click 'Add and Switch'
6. You should get error saying Invalid access token.
7. Type correct access token and click 'Add and Switch'
8. Account should be added and displayed as active

[dominiccooney]

Looks like a nice step forward. Some comments inline. TODOs may be appropriate at this point since this will be under heavy change for a while.

[dominiccooney]

I know we used to be saving the endpoint here, I assume now we are talking to the network now too... Can we show a spinner and when the result comes back, flip the UX at that point?

[pkukielka]

Done.

[dominiccooney]

Unless this is passed to some memoized thing, it is probably not worth memoizing... particularly since you're not memoizing onOpenChange or the onclick handler...

[pkukielka]

Done.

[danielmarquespt]

Looks good as a temporary solution until we built the unified design

[mkondratek]

When I run it for the first time for the instance I had two accounts logged in (dotcom and enterprise) I saw 3 accounts in the list to switch account

• http://sourcegraph.com
• https://sourcegraph.com
• https://sourcegraph.sourcegraph.com

I switched to http one out of curiosity and it presented me the log in screen.
I tried to log in using http://sourcegraph.com - the error happens silently in the logs

After I logged in to dotcom https I see this:

[pkukielka]

Looks like a nice step forward. Some comments inline. TODOs may be appropriate at this point since this will be under heavy change for a while.

Thanks @dominiccooney .
In fact I already have adding and removing accounts flow 85% working so I think I will just push rest of the changes to this PR tomorrow.

[kalanchan]

nice typescript skills!

[mkondratek]

lgtm