Add DevopsAdoptionTableCellFlag component

What does this MR do?

This component is needed in order to display the adoption status of an item, i.e. true or false - within the Devops Adoption feature.

The only way to test this locally would be to test the change in !47164 (merged).

I've opted to open this separate MR in order to iterate while blocked on other parts of the main MR. This also enables me to produce nice and small, easily reviewable MRs 🕺

The border is $gray-300 and the fill is $indigo-600

Feature flag rollout issue: #271568 (closed)

Screenshots (strongly suggested)

The component is the small circles within the table 😅

Enabled	Disabled

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

Related to #271249 (closed)