fix: ci-2234 check for tagName for comparison

[debugwand]

Describe your changes

This change allows us to apply delegation to an area of the page that applies a shadow root.

This checks for the existence of the tagName property on an element before running lowerCase() on it, as if this is undefined or null this will throw an error. If an element applies a shadow root, that will return as a document fragment when looping through the parent nodes, and these do not have the tagName property.

Issue ticket number and link

https://financialtimes.atlassian.net/jira/software/c/projects/CI/boards/1653?assignee=5be57e310e625003a46e9693&selectedIssue=CI-2234

Link to Figma designs

N/A

Checklist before requesting a review

• I have applied percy label for o-[COMPONENT] or chromatic label for o3-[COMPONENT] on my PR before merging and after review. Find more details in CONTRIBUTING.md
• If it is a new feature, I have added thorough tests.
• I have updated relevant docs.
• I have updated relevant env variables in Doppler.

[debugwand]

there are other problems that are triggered when attaching to a shadow root, so closing this. I'll find another way.