Public search - Decision outcome filter does not impact results

**Describe the Bug**
On public search, when user selects any option in the Decision Outcome filter, the results are not impacted.

**Expected Behaviour**
The decision outcome filter returns accurate counts according to the option selected.

**Actual Behaviour**
Selecting an option in the Decision Outcome field does not impact the results.

** Steps To Reproduce**
Steps to reproduce the behaviour:
1. Go to Public Search
2. Click on Decision Outcome, select any option
3. Run the search
4. AR: See 0 results. ER: Results are updated to show Approved results.

Alternatively, configure a search such as Region = Interior, run the search, then add Decision Outcome = Approved and re-run the search -- Application results should change to only show Approved applications in the Interior, but currently the results are unchanged.

Confirm this task meets our team [**Definition of Ready (DoR)**](https://www.figma.com/board/XmNkN600aAVWFCBmSDdt10/Team-Documents?node-id=1-2&t=Xjd6nHZZ7YlnoOrD-4) before moving to the **Next Sprint** column.

Confirm this task meets our team [**Definition of Done (DoD)**](https://www.figma.com/board/XmNkN600aAVWFCBmSDdt10/Team-Documents?node-id=3-21&t=Xjd6nHZZ7YlnoOrD-4) before moving to the **Done** column.

Start at the Public Search entry point and trace how the Decision Outcome selection is included in the search request and applied to returned results. Reproduce the Interior plus Approved scenario, then verify that counts and results update to show only applications matching the selected outcome.

Written by the indexing model from the issue text.