Reverting the customVariable type

Author: eduard13

app/code/Magento/Variable/Test/Mftf/Data/VariableData.xml

@@ -11,7 +11,7 @@
     <entity name="_defaultVariable" type="cms_page">
         <data key="city"> Austin </data>
     </entity>
-    <entity name="customVariable" type="variable">
+    <entity name="customVariable" type="cms_page">
         <data key="code" unique="suffix">variable-code</data>
         <data key="name">Test Variable</data>
         <data key="html"> Sample Variable </data>