Update ElasticDeleteProjectWorker to not be dependent upon project join

What does this MR do?

Related to #273234 (closed)

Remove reliance on parent joins for Elasticsearch query to delete associated records in ES when a project gets deleted. For issues, notes, and milestones that means just querying by project_id which each of them index already. For merge requests, target_project_id is used since that is what project_id is aliased to in the model.

Added one test to spec to verify all data is removed.

Screenshots (strongly suggested)

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