lib/model: Switch the remoteFolderState default value to valid (#8275)

Showing all folders from disconnected or paused remote devices as
unaccepted would be a lot of false positives.  As we cannot know
whether the remote has accepted while it doesn't have an active
connection, let's better report false negatives, as in assuming the
folders are accepted.

lib/model/folderstate.go

@@ -55,9 +55,9 @@ func (s folderState) String() string {
 type remoteFolderState int
 
 const (
-	remoteNotSharing remoteFolderState = iota
+	remoteValid remoteFolderState = iota
+	remoteNotSharing
 	remotePaused
-	remoteValid
 )
 
 type stateTracker struct {