Fix parent node id remapping (#198)

[MarcusLongmuir]

This PR fixes an issue where parent node ids were being incorrectly attempted to be remapped when resolving changes to target elements. The node ids that were being used were already remapped so this remapping looking was incorrect.

This issue was rather difficult to hit as you would need to:

• Reload a document
• Have the diff between the documents result in remapping node ids
• Cause a mutation to an element whose parent id collided with one of the remapped ids (even if the change itself was nothing to do with the nodes that were actually remapped)

A regression test that was used to root cause the issue has been added.

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What kind of changes does your PR introduce? (check at least one)

• Bugfix

Does your PR introduce a breaking change? (check one)

• No

Does your PR fulfill the following requirements?

• All tests are passing
• The title references the corresponding issue # (if relevant)