Remove backoff from dashboard call

Background

Some requests to the backend must be retried while the backend prepares them in the background, the retrying process is called backoff. This is normally used for request to go out of the GitLab intance to other systems like Prometheus or ElasticSearch to fetch data.

What does this MR do?

AFAIK the dashboard does not have to be retried as it is already available immediately.

However, when I removed the backoff code, one of the tests failed. I would like to look into why.

Screenshots

N/A

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