fix(VAvatar): properly render when using a svg (#8423)

fixes #8367

Right v-avatar only really works properly with <img> elements. There are cases where <svg> is preferred such as identicon graphics generated client-side. This change makes <svg> work as expected.

packages/vuetify/src/components/VAvatar/VAvatar.sass

@@ -11,6 +11,7 @@
   vertical-align: middle
 
   img,
+  svg,
   .v-icon,
   .v-image,
   .v-responsive__content