wrap constructable sytlesheets in try for browser compatbility

[MichaelWest22]

Description

iOS/safari was late at supporting Constructable CSS stylesheet which we now use as a cleaner way to adopt indicator styles instead of manual style tag injection. For better support of older iOS 15 safari etc we should wrap this in a try fetch so it does not break applications.

Corresponding issue:
#4023

Testing

Please explain how you tested this change manually, and, if applicable, what new tests you added. If
you're making a change to just the website, you can omit this section.

Checklist

• I have read the contribution guidelines
• 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