added hex color representation to semantic segmentation label config

com.unity.perception/Editor/GroundTruth/SemanticSegmentationLabelConfigEditor.cs

                         .FindPropertyRelative(nameof(SemanticSegmentationLabelEntry.label)));
                     addedLabel.colorField.BindProperty(m_SerializedLabelsArray.GetArrayElementAtIndex(i)
                         .FindPropertyRelative(nameof(SemanticSegmentationLabelEntry.color)));
+                    addedLabel.hexLabel.text = "#"+ColorUtility.ToHtmlStringRGBA(m_SerializedLabelsArray.GetArrayElementAtIndex(i)
+                        .FindPropertyRelative(nameof(SemanticSegmentationLabelEntry.color)).colorValue);
                 }
             }
 
         protected override string UxmlPath => k_UxmlDir + "ColoredLabelElementInLabelConfig.uxml";
 
         public ColorField colorField;
+        public Label hexLabel;
 
         public ColoredLabelElementInLabelConfig(LabelConfigEditor<SemanticSegmentationLabelEntry> editor, SerializedProperty labelsArray) : base(editor, labelsArray)
         { }
             colorField = this.Q<ColorField>("label-color-value");
+            hexLabel = this.Q<Label>("label-color-hex");
 
             colorField.RegisterValueChangedCallback((cEvent) =>
             {
 
                     Debug.LogWarning("A label with the chosen color " + cEvent.newValue + " has already been added to this label configuration.");
                 }
+
+                hexLabel.text = "#"+ColorUtility.ToHtmlStringRGBA(colorField.value);
             });
 
         }

com.unity.perception/Editor/GroundTruth/Uxml/ColoredLabelElementInLabelConfig.uxml

     <VisualElement class="added-label" style="padding-top: 3px;">
         <Button name="remove-button" class="labeling__remove-item-button"/>
         <VisualElement class="generic-hover"
-                       style="flex-direction: row; padding: 3px 0 3px 6px; margin-left: 3px; margin-right: 3px; border-width: 1px; border-color: #555555; border-radius: 4px;">
-            <editor:ColorField name="label-color-value" style="min-width : 60px; max-width: 60px; align-self:center;"/>
+                       style="min-width : 137px; flex-direction: row; padding: 3px 0 3px 6px; margin-left: 3px; margin-right: 3px; border-width: 1px; border-color: #555555; border-radius: 4px;">
+            <editor:ColorField name="label-color-value" style="min-width : 60px; max-width: 60px; align-self:center; margin:2px"/>
+            <Label name="label-color-hex" style="font-size: 11; min-width : 60px; max-width: 60px; align-self:center;"/>
         </VisualElement>
         <TextField name="label-value" class="labeling__added-label-value"/>
         <VisualElement style="min-width:20px; flex-direction: row; display:none">