fix(vtreeview): a node no longer sets indeterminate state based on pa…

…rent, only by it's children

A Treeview node no longer sets it's indeterminate state based on it's parent. The indeterminate
state is only set by the default state, the node's previous state, or by the states of the node's
children.

fix vuetifyjs#8256

packages/vuetify/src/components/VTreeview/VTreeview.ts

@@ -214,7 +214,6 @@ export default mixins(
         // This fixed bug with dynamic children resetting selected parent state
         if (!this.nodes.hasOwnProperty(key) && parent !== null && this.nodes.hasOwnProperty(parent)) {
           node.isSelected = this.nodes[parent].isSelected
-          node.isIndeterminate = this.nodes[parent].isIndeterminate
         } else {
           node.isSelected = oldNode.isSelected
           node.isIndeterminate = oldNode.isIndeterminate