[Embeddables Rebuild] Allow Save and Return for React Embeddables

[ThomThomson]

Summary

Simple fix for #178554. There is already an add new panel method that takes into account both the new and old embeddable systems, this PR uses it instead of addNewEmbeddable.

[ThomThomson]

/ci

[elasticmachine]

Pinging @elastic/kibana-presentation (Team:Presentation)

[nreese]

I tried running these changes in #178158 and got the error below when adding a map react embeddable. To set the the environment, pull #178158 and copy src/plugins/dashboard/public/dashboard_container/embeddable/create/create_dashboard.ts from this PR

[ThomThomson]

Oh dang, that's the error I got, but I assumed it was due to my changes to your maps refactor. Let me take a look.

[ThomThomson]

@nreese I looked into the error today. Turns out that it's failing when inject is called as part of the deserializeState method when it is called on the last saved state.

We need to call deserializeState on the last saved state so that they have the same base for state diffing. In this case though, there is no last saved state (the panel is brand new), so deserializeState gets called with the state as undefined. This is to be expected. The deserializeState method must be coded defensively, because rawState is a completely unknown type.

I was able to work around the issue by modifying the inject code to not throw when the given state is undefined, we should discuss this.

[ThomThomson]

@elasticmachine merge upstream

[kibana-ci]

💚 Build Succeeded

• Buildkite Build
• Commit: cdcb218

Metrics [docs]

Async chunks

Total size of all lazy-loaded chunks that will be downloaded as the user navigates the app

id	before	after	diff
dashboard	385.6KB	385.5KB	-30.0B

History

• 💚 Build #198367 succeeded ff27323
• 💚 Build #197524 succeeded d830e2a

To update your PR or re-run it, just comment with:
@elasticmachine merge upstream

[nreese]

LGTM
code review and tested in chrome with react_map_embeddable branch