Added group by on pull-request page

Description and Impact
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> What impact does this change have for production?

Deploy Plan
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> Does Infrastructure need to know anything special about this deploy?

Rollback Plan
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* To roll back this change, revert the merge with: `git revert -m 1 MERGE_SHA` and perform another deploy.

URLs
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> Links to bug tickets or user stories.

QA Plan
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> Fill in scenarios below. Review [QA Best Practices](https://source.sportngin.com/page/show/1227795-qa-best-practices).

#### Happy Path Scenarios
* Happy Path scenario 1
* Happy Path scenario 2

#### Additional Scenarios (Edge Case, Negative, etc.)
* Edge case scenario 1
* Edge case scenario 2

#### Regression Scenarios
* Regression item on related feature 1
* Regression item on related feature 2