Added AI similar issues workflow

[craigloewen-msft]

Adds a GitHub workflow to try and show similar issues to newly filed issues. Will look like this:

[learn-build-service-prod[bot]]

Learn Build status updates of commit 5eaa0b5:

:white_check_mark: Validation status: passed

File	Status	Preview URL	Details
.github/workflows/similarissues.yml	:white_check_mark:Succeeded

For more details, please refer to the build report.

For any questions, please:

• Try searching the learn.microsoft.com contributor guides
• Post your question in the Learn support channel