[Canvas] Use original input when updating existing embeddable

[cqliu1]

Summary

This fixes a bug where the time range set on an embeddable in Canvas would get reset after editing the embeddable in it's respective editor and returning to Canvas.

Now if there is an incoming embeddable with the same id as an existing element, this extracts the original embeddable input from the expression and uses it as the base input object for the incoming embeddable input.

To test:

• Create a workpad.
• Create an embeddable element.
• Change the time range to last 2 weeks on the embeddable.
• Click on the action menu and edit the embeddable.
• Click save and return.

The time range on the embeddable should still show Last 2 weeks instead of resetting to Last 15 minutes.

Checklist

Delete any items that are not applicable to this PR.

• Any text added follows EUI's writing guidelines, uses sentence case text and includes i18n support
• Documentation was added for features that require explanation or tutorials
• Unit or functional tests were updated or added to match the most common scenarios
• Any UI touched in this PR is usable by keyboard only (learn more about keyboard accessibility)
• Any UI touched in this PR does not create any new axe failures (run axe in browser: FF, Chrome)
• If a plugin configuration key changed, check if it needs to be allowlisted in the cloud and added to the docker list
• This renders correctly on smaller devices using a responsive layout. (You can test this in your browser)
• This was checked for cross-browser compatibility

Risk Matrix

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Before closing this PR, invite QA, stakeholders, and other developers to identify risks that should be tested prior to the change/feature release.

When forming the risk matrix, consider some of the following examples and how they may potentially impact the change:

Risk	Probability	Severity	Mitigation/Notes
Multiple Spaces—unexpected behavior in non-default Kibana Space.	Low	High	Integration tests will verify that all features are still supported in non-default Kibana Space and when user switches between spaces.
Multiple nodes—Elasticsearch polling might have race conditions when multiple Kibana nodes are polling for the same tasks.	High	Low	Tasks are idempotent, so executing them multiple times will not result in logical error, but will degrade performance. To test for this case we add plenty of unit tests around this logic and document manual testing procedure.
Code should gracefully handle cases when feature X or plugin Y are disabled.	Medium	High	Unit tests will verify that any feature flag or plugin combination still results in our service operational.
See more potential risk examples

For maintainers

• This was checked for breaking API changes and was labeled appropriately
  Fixed server interpreter setup

Register external functions in canvas_plugin_src plugin def

[elasticmachine]

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

[mshustov]

removing core team since I don't see any changes related to our domains

[kibanamachine]

💛 Build succeeded, but was flaky

• Buildkite Build
• Commit: eecc31c
• Storybooks Preview

Test Failures

• [job] [logs] Default CI Group #1 / watcher app watcher_test create and save a new watch

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
canvas	1.0MB	1.0MB	+289.0B

History

• 💛 Build #1281 was flaky 931e68a96e031ccf7e1334adac6324bf8a59a25b
• 💔 Build #1155 failed c9eb937764107ad36f72241a2551e3da9b95379c

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

[crob611]

Code LGTM