[Stretch] Coordinate with App Bridge team for leave confirmation shake

[sophschneider]

App bridge next has shake but not app bridge host bc they have their own leave confirmation component

https://github.com/Shopify/app-bridge/blob/main/packages/app-bridge-host/src/components/ContextualSaveBar/LeaveConfirmation/LeaveConfirmation.tsx

This needs to be updated to use the new shake. Their team said they would do it but it will be after summer editions

More context https://github.com/Shopify/polaris-internal/issues/356

Additionally there is an upgrade path for apps > move to app bridge next

[sophschneider]

I have this PR up https://github.com/Shopify/app-bridge/pull/3241 that successfully implements the shake!

Only issue is I can't currently find a way to access beta flags in app bridge. For now, we will have to wait until 100% rollout is stable, and then ship this

[sophschneider]

Setting this as blocked until we have rolled out polaris_dynamic_top_bar_and_reframe to 100% and is stable

[sophschneider]

Blocked by https://github.com/Shopify/polaris-internal/issues/87

[sophschneider]

Moving this back to blocked as snapit is broken in app bridge, asked for some help in fixing it

[sophschneider]

I put this PR up https://github.com/Shopify/app-bridge/pull/3241

the app bridge team needs to review and merge, since I don't have merging permissions in that repo. Made a post in their app ui channel

[sophschneider]

In this PR https://github.com/Shopify/app-bridge/pull/3241#issuecomment-2296467416

Team was concerned about the breaking changes this would require. We have passed of the PR that adapts the shake into AB3, team can do whatever option they think is best moving forward