Add snowplow analytics for clicking search result

What does this MR do?

Add the relevant data attributes to track click events on search results. This will help us track how useful our searches are for people and help us detect when we may have made changes that impact the usefulness of results.

This is done based on the guide at https://docs.gitlab.com/ee/development/telemetry/snowplow.html#tracking-in-haml-or-vue-templates .

Screenshots

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 #240731 (closed)