settings shows user's timezone, provide ptr to fetch user

[krugerk]

Summary

Settings shows the user's timezone but only a few places in the app were fetching the user: fetching default notification settings (entering the default notification settings screen) and upon signing in.
This MR allows the user to trigger a fetch of the User endpoint via a Pull-To-Refresh on the Settings screen.

For UI changes including screenshots of before and after is great.

Validation

used the app in the simulator
change the timezone at the website
tapped around in the app again both entering settings and pull to refresh from settings

Fixes #507 and helps out with #360

[theospears]

I have a PR in the works which will update User every time goals are updated (as a side effect of moving to use diff_since and incremental goal update). If that change is merged, would you still want to do this?

[krugerk]

I have a PR in the works which will update User every time goals are updated (as a side effect of moving to use diff_since and incremental goal update). If that change is merged, would you still want to do this?

It is a very basic implementation as is. Of course if user is being fetched more often anyway, then one like this at the settings screen is perhaps too basic.
I think it is fine like this for now and maybe yours with using diff_since makes it moot.

[theospears]

There's some interesting nuance to lifetimes here.

It might be tempting to do this:

          guard let self = self else { return }

But it's not quite right, as the view might be dismissed while waiting for the refreshUser call to complete, and in that case we don't want to hold on to self.

Maybe worth a comment making this clear?

[krugerk]

as in,

@objc private func fetchUser() {
        Task { [weak self] in
            self?.tableView.isUserInteractionEnabled = false

            try? await ServiceLocator.currentUserManager.refreshUser()

            guard let self else { return }
            self.tableView.reloadData()
            self.tableView.layoutIfNeeded()
            self.tableView.refreshControl?.endRefreshing()
            
            self.tableView.isUserInteractionEnabled = true
        }
    }