MC-5054: User Can Bypass File Type Validation In PageBuilder's File Upload Spots

Remove unused data keys in PageBuilderBackgroundImage_InvalidMimeType

Author: danmooney2

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

@@ -219,13 +219,9 @@
         <data key="errorMessage">We don't recognize or support this file extension type.</data>
     </entity>
     <entity name="PageBuilderBackgroundImage_InvalidMimeType" type="pagebuilder_background_image_property">
-        <data key="name">Background Image</data>
         <data key="section">background</data>
         <data key="fieldName">background_image</data>
         <data key="value">not-a.png</data>
-        <data key="fileName">not-a</data>
-        <data key="extension">png</data>
-        <data key="path">wysiwyg</data>
         <data key="errorMessage">File validation failed.</data>
     </entity>
     <!-- Background Mobile Image -->