[Canvas] Make Canvas Saved objects share-capable

[crob611]

Workpads and Custom Elements are currently nameSpaceType: single. It should be updated to multiple_isolated per #100489

Blocked by the saved object references portion of #101639

[elasticmachine]

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

[jportner]

Note that this also entails changing the client and server API calls to use the new savedObjectsClient.resolve() API (instead of savedObjectsClient.get()), and handle the three different outcomes ('exactMatch', 'aliasMatch', and 'conflict'). See more details in the linked meta issue #100489.

[jportner]

In case anyone is following this issue but not the linked meta-issue (#100489):

I published the Sharing Saved Objects developer guide, please take a look before proceeding with the implementation. And of course, please reach out if you run into any problems!

[stacey-gammon]

@jportner, @clintandrewhall - should this be labeled as an 8.0 blocker?

[jportner]

@jportner, @clintandrewhall - should this be labeled as an 8.0 blocker?

Yes, I think so.
Corey already has a PR open with the majority of the work done.

[jportner]

Hey @crob611 I just wanted to check on the status of this to see if it's on track for the 8.0 release