Global Search - Redesign Issue Results Title

What does this MR do?

Closes #233240 (closed)

This change updates the search results page for Issues. It implements the design proposed in the issue above.

Important Notes for Scalability

• Currently the search results are handled explicitly by their own file, so this change will make the rest of the search results look significantly different.
• These results are still in HAML, we may look to approaching the search results more generically from a higher level so we don't need to manage each results view separately.
• Refactoring the results into Vue would be a good next step as we can tackle both of the above points while also moving the views into our frontend framework.

Screenshots

	before	after
Issues Results Page

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 #233240 (closed) cc/ @gitlab-org/search-team