[plotter] do not force the scalebar if not wanted in embeded mode

plotter.py

@@ -559,7 +559,7 @@ class Plotter(Aggregator, BaseProcessor):
         transform=None,
         vmin=None,
         vmax=None,
-        scalebar=False,
+        scalebar=None,
         scalebar_size=1,
         axes=True,
         colorbar=True,
@@ -578,7 +578,9 @@ class Plotter(Aggregator, BaseProcessor):
 
         if embeded:
             axes = False
-            scalebar = True
+            # Put a scalebar by default
+            if scalebar is None:
+                scalebar = True
 
         if center_space:
             center = self.current_processor.get_attribute("/maps", "center")