Usage Ping for embedded Grafana charts Part 2

What does this MR do?

Overview

Count total issues in an instance where a Grafana chart has been embedded

Part of #31385 (closed)

Implementation Details

Checks for the grafana url prefix by querying the issue description.

Performance Notes

This code may be fairly long running on some hosts with many issues. I had initially discussed using a redis cache and background job to avoid timeouts but I don't think that is necessary since the usage ping is already run as a background job.

UsageData.data is called via a GET request but it is called without force_refresh: false as an argument so it should use the cache from the background job rather than re-calculating stats. The usage ping worker does do an http request to POST metrics back to gitlab, but the statistics should be gathered at that point, so we shouldn't have to work about request timeouts.

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

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

Part of #31385 (closed)