Update keybinding widget when keybindings change

[colin-grant-work]

What it does

In the review of #8776, it was noticed that the keybinding widget does not update in response to changes to keybindings, so that at startup, it can get stuck displaying default values before user or workspace values are processed.

How to test

1. Modify a keybinding.
2. With the keybinding widget open, restart the application.
3. Find the modified keybinding.
4. Observe that modified keybinding is shown rather than the default.

Review checklist

• As an author, I have thoroughly tested my changes and carefully followed the review guidelines

Reminder for reviewers

• As a reviewer, I agree to behave in accordance with the review guidelines

[vince-fugnitto]

I confirmed that the changes work as expected 👍

• updated keybindings are properly reflected on reload
• the query is restored on reload, the view correctly restores the state and re-searches