Fix card comments xml

[sean-yeoh]

Summary

Currently, card comments are exported in the XML but not in the correct node.

The exported XML looks like this, notice the individual comment's attributes are direct children inside the <comments> node, but they should be in the <comment> node instead.

You can see the difference by comparing it to an issue's comment.

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Check List

• Added a CHANGELOG entry

[aapomm]

Suggested change

	- Project export: Fix card comments not exported
	- Project export: Fix export for comments in cards