Utilize GitLab UI icon component: pipelines to vue_merge_request_widget

What does this MR do?

This replaces all the usages of ~/vue_shared/components/icon.vue with the corresponding GitLab UI component for all components from pipelines to vue_merge_request_widget (alphabetically).

In a previous MR 0 we already replaced the internal implementation with the GitLab UI component. This should allow us to migrate all usages without any test failures relating to the differences in their implementation.

The actual deletion of the file will be done in a follow-up in case we have missed an instance or someone introduces a new one in the meanwhile.

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