Include subgroup issues in iteration list

What does this MR do?

Add the includeSubgroups (added in !39279 (merged)) to group iteration issues queries. Updates both the summary (gray boxes at the top) and the issues list.

FE for #229433 (closed)

Screenshots

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides