fix(model): properly health-check up-to-date folders (fixes #10546) (#10773)

Previously we'd skip the health check for an up-to-date folder, so it
would continue looking up-to-date even when the folder path missing.

---------

Signed-off-by: Jakob Borg <jakob@kastelo.net>

lib/model/folder_sendonly.go

@@ -98,7 +98,6 @@ func (f *sendOnlyFolder) override(ctx context.Context) error {
 	f.sl.InfoContext(ctx, "Overriding global state ")
 
 	f.setState(FolderScanning)
-	defer f.setState(FolderIdle)
 
 	batch := NewFileInfoBatch(func(files []protocol.FileInfo) error {
 		f.updateLocalsFromScanning(files)