Duplicate programs can be selected in the comparison filter causing console error

[mukeshpanchal27]

Describe the bug

The Programs Comparison filter allows duplicate program selections, leading to console errors when trying to compare.

Steps to reproduce

1. Set up a WordPress site running version ≥ 6.1.
   • The filter cannot open on versions < 6.1 (see #1920).
2. Navigate to the Reports → Programs tab.
3. Click on the Programs filter and choose the Comparison filter.
4. Use the search input to select a campaign.
5. Search again and select the same campaign (duplicate).
6. Click the Compare button.
7. Observe the error in the browser console.

Expected behaviour

The filter should prevent selecting duplicate programs in the comparison search.

Actual behaviour

The filter allows duplicate selections, which results in a JavaScript console error.

Screenshot