[Session] Extract selectAccount out

[gaearon]

This is similar to #3811 in spirit and is based on the same insight. selectAccount has nothing to do with session management per se, it's just a wrapper around initSession that tracks the progress of that call. It makes sense to make such state tracking local to where the action was triggered in the UI code. So I'm moving that state back into components.

I moved the isSwitchingAccounts state variable out of the Session API and into the calling components which now call initSession directly. For AccountList, I've plumbed it down from the component that owns the switch press handler.

Test Plan

Use the account switcher, both the popover and the settings one. It feels a bit janky but I replicated the existing logic. This should make it a bit easier to change the UI logic if we'd like to later because it's all local state now.

[render]

Your Render PR Server URL is https://social-app-pr-3812.onrender.com.

Follow its progress at https://dashboard.render.com/web/srv-cophlbsf7o1s73fikrpg.

[github-actions]

Old size	New size	Diff
6.85 MB	6.85 MB	-107 B (-0.00%)

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[haileyok]

Small thing when selecting an account that I noticed. My selection is highlighted as long as I am still pressing in, but as soon as I release the highlight moves down to "Other Account"

RocketSim_Recording_iPhone_15_Pro_6.1_2024-05-02_07.55.24.mp4