Add parent argument to Bulk Update Service

What does this MR do?

#12687 (closed)

When bulk editing issuables at a Group level, we need to verify that these issuables belong to that group or a descendant.

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

Closes #12687 (closed)