AFC_Bridge is not an aircraft or scenery. Add-on aircraft or scenery subdirectories contain files that identify the add-on to the Content Manager. AFC_Bridge shows as uninstalled in Content Manager because its files are different than aircraft or scenery add-ons.
For the addons in the Community directory Content Manager is only an inventory list. It doesn’t and cannot “manage” anything in Community.
As long as AFC_Bridge is in your Community directory it is installed. In other words, don’t pay attention to what Content Manager says.
I know this is strange and not documented at all but this is how Asobo has been delivering many undocumented features.