appview: nil check when getting profile

Signed-off-by: Will Andrews <did:plc:dadhhalkfcq3gucaq25hjqon>

appview/state/profile.go

···
 		log.Printf("getting profile data for %s: %s", user.Did, err)
 	}
 
+	if profile == nil {
+		return
+	}
+
 	profile.DefaultKnot = r.Form.Get("default-knot")
 
 	tx, err := s.db.BeginTx(r.Context(), nil)