fix(VStepperVertical): correct avatar alignment (#21797)

fixes #21792

Author: J-Sek

packages/vuetify/src/labs/VStepperVertical/VStepperVerticalItem.sass

@@ -44,6 +44,7 @@
   background: rgba(var(--v-theme-surface-variant), var(--v-medium-emphasis-opacity))
   color: rgb(var(--v-theme-on-surface-variant))
   transition-property: background
+  align-self: start
 
   .v-icon
     font-size: .875rem