MC-3864: Fix alpha value in background colour

- Update test to actually check alpha value from colour picker

Author: davemacaulay

app/code/Magento/PageBuilder/Test/Mftf/Data/BackgroundFormData.xml

@@ -74,9 +74,9 @@
         <data key="section">background</data>
         <data key="fieldName">background_color</data>
         <data key="value">rgba(0, 0, 254, 0.92)</data>
-        <data key="rgb">rgb(0, 0, 254)</data>
-        <data key="hex">#0000fe</data>
-        <data key="editPanelValue">#0000fe</data>
+        <data key="rgb">rgba(0, 0, 254, 0.92)</data>
+        <data key="hex">rgba(0, 0, 254, 0.92)</data>
+        <data key="editPanelValue">rgba(0, 0, 254, 0.92)</data>
     </entity>
     <entity name="PageBuilderBackgroundColor_HSL_Orange" type="pagebuilder_background_color_property">
         <data key="name">Background Color</data>