fix(VIcon): add mdi set only if defaultSet is mdi (#18876)

Co-authored-by: John Leider <john@vuetifyjs.com>

packages/vuetify/src/composables/icons.tsx

@@ -167,23 +167,29 @@ export const VClassIcon = defineComponent({
 })
 export type VClassIcon = InstanceType<typeof VClassIcon>
 
-export const defaultSets: Record<string, IconSet> = {
-  svg: {
-    component: VSvgIcon,
-  },
-  class: {
-    component: VClassIcon,
-  },
+function genDefaults (): Record<string, IconSet> {
+  return {
+    svg: {
+      component: VSvgIcon,
+    },
+    class: {
+      component: VClassIcon,
+    },
+  }
 }
 
 // Composables
 export function createIcons (options?: IconOptions) {
+  const sets = genDefaults()
+  const defaultSet = options?.defaultSet ?? 'mdi'
+
+  if (defaultSet === 'mdi' && !sets.mdi) {
+    sets.mdi = mdi
+  }
+
   return mergeDeep({
-    defaultSet: 'mdi',
-    sets: {
-      ...defaultSets,
-      mdi,
-    },
+    defaultSet,
+    sets,
     aliases: {
       ...aliases,
       /* eslint-disable max-len */
@@ -235,7 +241,7 @@ export const useIcon = (props: Ref<IconValue | undefined>) => {
       setName => typeof icon === 'string' && icon.startsWith(`${setName}:`)
     )
 
-    const iconName = iconSetName ? icon.slice(iconSetName.length + 1) : icon
+    const iconName = iconSetName?.startsWith('svg') ? icon.slice(iconSetName.length + 1) : icon.replace(':', '-')
     const iconSet = icons.sets[iconSetName ?? icons.defaultSet]
 
     return {