Remove deprecated API usage

[flash1293]

There are a few deprecated APIs in use in VisEditors plugins which should be fixed.

onAppLeave in lens / visualizations

Instead of onAppLeave, the block method of the history object passed down to the mount function of the app should be used (

kibana/x-pack/plugins/lens/public/plugin.ts

Line 316 in 0ea741d

mount: async (params: AppMountParameters) => {

).

It's a thin wrapper around the block method of the history object used for routing: https://github.com/remix-run/history/blob/3e9dab413f4eda8d6bce565388c5ddb7aeff9f7e/docs/blocking-transitions.md

It seems like the easiest way to implement this is to introduce a shimming layer which keeps the onAppLeave semantics and uses history.block under the hood:

• if onAppLeave is called, execute the passed in callback with an actions object
• Afterwards, check what got called on the actions object
• If default got called, call the unregister callback from history.block if it got called before
• If confirm got called, call history.block if it didn't get called yet and render the modal in the callback and on a confirmation unblock and retry the transaction like in the example in https://github.com/remix-run/history/blob/3e9dab413f4eda8d6bce565388c5ddb7aeff9f7e/docs/blocking-transitions.md

migration warning in lens (done)

Should use warn instead

injectedMetadata in vega (done)

Should have an optional dependency on the maps_ems plugin and get it from there via contract

[elasticmachine]

Pinging @elastic/kibana-vis-editors @elastic/kibana-vis-editors-external (Team:VisEditors)

[flash1293]

Getting rid of onAppLeave is blocked on #132597, #132599 and #132600