TreeView: Children of preselected items don't get updated as expected

[silvalaura]

Describe the bug

pt1ch1.1 should be selected even though it’s not in the list of preselected (because it’s the child of a preselected item), but it should also appear on the list of tags and count of tags

To Reproduce Steps to reproduce the behavior:

1. Go to https://storybook-preview-dev--upbeat-sinoussi-f675aa.netlify.app/?path=/story/treeview--complex
2. Notice the list of preselectedItems:

   preselectedItems: [
   { itemId: 'pt1ch1', checkedStatus: IndeterminateCheckboxStatus.checked },
   { itemId: 'pt1', checkedStatus: IndeterminateCheckboxStatus.indeterminate },
   { itemId: 'pt2ch4', checkedStatus: IndeterminateCheckboxStatus.checked },
   {
     itemId: 'pt2ch5.1.1',
     checkedStatus: IndeterminateCheckboxStatus.checked,
   },
   { itemId: 'pt2ch5.2', checkedStatus: IndeterminateCheckboxStatus.checked },
   { itemId: 'pt2ch5.3', checkedStatus: IndeterminateCheckboxStatus.checked },
   ],

3. Notice that pt1ch1.1 is selected even though it's not listed in the array below. This is expected behavior because it's a child of a selected item
4. Also notice that in the tags below, pt1ch1.1 does not appear
5. This is also causing the tag total number to be in correct. This example should have 10 tags

Expected behavior

• This example should have 10 tags, including pt1ch1.1.
• We should also confirm this is behaving as expected with different combinations of preselectedItems, some parents, some children, etc.

[silvalaura]

This will be indirectly fixed by @vitaliirumiantsev-cengage in #1446