fix(VSwitch/VCheckbox): color not applied if value is 0/false (#9431)

Author: DRoet

packages/vuetify/src/components/VCheckbox/VCheckbox.ts

@@ -60,7 +60,7 @@ export default Selectable.extend({
       if (this.disabled && !this.inputIndeterminate) return undefined
       if (this.hasError && this.shouldValidate) return 'error'
       if (this.hasSuccess) return 'success'
-      if (this.hasColor) return this.computedColor
+      if (this.hasColor !== null) return this.computedColor
       return undefined
     },
   },

packages/vuetify/src/components/VSwitch/VSwitch.ts

@@ -59,7 +59,7 @@ export default Selectable.extend({
     validationState (): string | undefined {
       if (this.hasError && this.shouldValidate) return 'error'
       if (this.hasSuccess) return 'success'
-      if (this.hasColor) return this.computedColor
+      if (this.hasColor !== null) return this.computedColor
       return undefined
     },
     switchData (): VNodeData {