Global Open Asset Dialog has a duplicate filter for "other developers assets"

CL# 4832458 enabled bAddFilterUI, which causes a SFilterList to be created for the global open asset dialog. This SFilterList causes a duplicate FFrontendFilter_ShowOtherDevelopers to be added to the FrontendFilters (as it's an inverse filter; SAssetPicker adds its own for the button in its UI).

Having two of these filters means that both need to be enable to see other developers assets, and as far as I can tell, this has been broken since 2014.

This should be updated so that when the filter UI is enabled, SAssetPicker doesn't add its own filter instance and instead shares the one from the SFilterList.

1. Open QAGame.
2. Press Shift+Alt+O to open the global open asset dialog.
3. Ensure that "Show Developers Content" is enabled under the "View Options".
4. Press the button in the UI to show other developers content.
5. Observe that nothing changes.

Expected: The button toggles the visibility of of other developers assets.

Workaround: Enable the "Other Developers" filter, under "Filters" -> "Other Filters". The button then works as expected.