Add expandable view to Terraform MR widget

What does this MR do?

We currently have an MR widget that displays Terraform information.

Example Widget: https://gitlab.com/emilyring/terraform-test/-/merge_requests/6

In a previous MR it was discussed that the widget is too large and needs to display inside an expandable content section.

This MR will

• Adds a reusable mr widget expandable component. Part of the previous discussion was that no standard design currently exists for MR Widgets. This is will NOT solve the issue, but it will offer a reusable component others can migrate to. It also offers a way to iterate on the expandable widget design.
• Updates the terraform widget to use the new component. It also adds a new header section to the Terraform Widget.
• Updates associated tests

Screenshots

multiple

valid

bad

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Availability and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• Tested in all supported browsers
• Informed Infrastructure department of a default or new setting change, if applicable per definition of done

Security

If this MR contains changes to processing or storing of credentials or tokens, authorization and authentication methods and other items described in the security review guidelines:

• Label as security and @ mention @gitlab-com/gl-security/appsec
• The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
• Security reports checked/validated by a reviewer from the AppSec team

Closes #222964 (closed)