Avoids await chains & unneeded function creations

* Add graph header context menu option to toggle mode

* Updates graph dependency

Closes #2252
Closes #2448
Follow-up to 5f95876a97

Ensures an update if subscription changed while hidden

Reworks webview registration
 - Splits out resolver from descriptor
 - Allows for more accurate typings

- disables "switch to branch" when on the current branch
- disables "open worktree" when already in it

- Renames `onDidChangeOther` to `onDidChangeAny` for accuracy
 - Removes `onDidChangeBeforeOverrides` as its unneeded (use `onDidChangeAny` instead)
Consolidates to `onDidChangeAny` where possible

- Controlled by the `gitlens.graph.experimental.location` setting

- converts participants label to an icon
- updates action links to buttons
- updates vertical alignment of table cells