Add NuGet package icon to package details page

What does this MR do?

Issue: #36422 (closed)

This MR adds the display of any NuGet package icon to the package-title component on the package details page. This icon will only show for NuGet packages that contain icon metadata.

Note: This MR also includes some tidy up of the style rules and test selectors used in the package-title component.

Screenshots

NuGet Package with Icon	NuGet Package without Icon	Other Package

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