Correct fill && correct tests

Author: VeraZab

src/components/fields/TraceSelector.js

@@ -86,7 +86,7 @@ class TraceSelector extends Component {
       updateContainer({
         type: 'scatter',
         mode: fullContainer.mode,
-        fill: 'none',
+        fill: fullContainer.fill || container.fill,
       });
     }
     this.fullValue = plotlyTraceToCustomTrace(container);

src/components/fields/__tests__/TraceSelector-test.js

@@ -81,7 +81,7 @@ describe('TraceSelector', () => {
     const innerDropdown = wrapper.find(Dropdown);
     innerDropdown.prop('onChange')('line');
 
-    const payload = onUpdateTraces.mock.calls[1][0];
+    const payload = onUpdateTraces.mock.calls[0][0];
     expect(payload.update).toEqual({
       fill: 'none',
       mode: 'lines',
@@ -107,7 +107,7 @@ describe('TraceSelector', () => {
     const innerDropdown = wrapper.find(Dropdown);
     innerDropdown.prop('onChange')('area');
 
-    const payload = onUpdateTraces.mock.calls[1][0];
+    const payload = onUpdateTraces.mock.calls[0][0];
     expect(payload.update).toEqual({fill: 'tozeroy', type: 'scatter'});
   });
 });