Handle help popovers

What does this MR do and why?

The widget now supports adding help popovers through props. There are two levels where we display the help popover:

1. The summary level (that is handled inside the widget.vue component)
2. The content row level (that is handled inside the widget_content_row.vue component)

Screenshots or screen recordings

How to set up and validate locally

1. You'll need an EE License
2. You'll need to have runners enabled (See $2408961 for setting up a runner)
3. Enable :refactor_security_extension to turn this feature on.

echo "Feature.enable(:refactor_security_extension)" | rails c

1. Import https://gitlab.com/gitlab-examples/security/security-reports
2. Create a new MR by editing a file
3. Go to the MR page and check the widget

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Related to #379086 (closed)