handle newContent processing of outerMorph that inserts new nodes

[MichaelWest22]

Description

During outerMorph swap style we make the newContent for later processing by using the fragment childNodes and adding in the target node so that either the existing morphed node or the newly inserted nodes will always be processed properly. But inside the morph we actually can clone the nodes with importNode() when inserting new nodes leaving the fragment childNodes disconnected and preventing the cloned in node being processed. To solve this I've removed the importNode which was done to prevent parent node mutations and instead captured the parent node children in the for loop to make the loop stable this way.

Corresponding issue:

Testing

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Checklist

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• I have targeted this PR against the correct branch (master for website changes, dev for
  source changes)
• This is either a bugfix, a documentation update, or a new feature that has been explicitly
  approved via an issue
• I ran the test suite locally (npm run test) and verified that it succeeded