[Uno] Remove Rns workaround

Talked to Jerome. This is a known Uno issue (see https://github.com/unoplatform/uno/issues/8750).

For now, we can just modify the default namespace in the csproj file? @Arlodotexe I think that'll be the simplest temporary solution.

> Working great on the linux build. I just appended `Rns` for now in the ProjectTemplate so new experiments will work as well.

Changing it for now should be fine as we're authoring the experiments, but it'd mean that VS would try and use it as the default namespace in new files which would break this pattern (though folders always make this problematic sometimes anyway for certain things).

_Originally posted by @michael-hawker in https://github.com/CommunityToolkit/Labs-Windows/issues/110#issuecomment-1124247914_

Esamina il ProjectTemplate e il file .csproj pertinente, quindi confronta lo spazio dei nomi predefinito attuale con l’issue di Uno collegata nella descrizione. Il lavoro è completato quando il workaround temporaneo per lo spazio dei nomi Rns viene rimosso senza compromettere gli esperimenti né lo spazio dei nomi usato per i nuovi file di Visual Studio.

Scritto dal modello di indicizzazione a partire dal testo della issue.