When creating/editing a plan of which it's project name value !== the default project, i.e. openshift-mtv, the select-able values of the "Target project" field are only the project of the selected "target provider" instead of proposing all available projects to be used as a target. 

2.10

Always

See screencast

only the target provider's project is selectable

All valid available projects should be selectable

we use values returned by:
 useProviderInventory<OpenShiftNamespace[]>({provider) 

instead of calling:
useK8sWatchResource<K8sResourceCommon[]>({isList: true, kind: isUpstream() ? 'Namespace' : 'Project'})  )