POS UI Ext: add dialog and camera scanner examples to docs

[vctrchu]

Resolves https://github.com/Shopify/pos-next-react-native/issues/36302

Background

Adds CameraScanner and Dialog examples and descriptions for props. I also updated some scanner examples that were using the incorrect syntax.

🎩

• Dialog
• CameraScanner

[github-actions[bot]]

We detected some changes in packages/*/package.json or packages/*/src, and there are no updates in the .changeset directory. If the changes are user-facing and should cause a version bump, run yarn changeset to track your changes and include them in the next release CHANGELOG. If you are making simple updates to repo configuration, examples, or documentation, you do not need to add a changeset.

[js-goupil]

ie if I hover over CameraScanner, this is what I see:

but if I hover over Tile, I see this (it lists all the properties nicely):

Also by having the property tags inside, we get this weird thing where we get two statements for one property: