fix(VVideo): background variant should fill the container

Author: J-Sek

packages/vuetify/src/labs/VVideo/VVideo.sass

@@ -143,8 +143,8 @@
     &--variant-background
       outline: none
       position: absolute
+      inset: 0
       pointer-events: none
-      height: 100%
 
       > .v-video__content
         width: 100%