New lint: potential bug with assigning a value to a tracked property

[NullVoxPopuli]

Example:

class Demo extends Component {
  @tracked foo = this.someProperty

  @cached 
  get someProperty() {
    return this.args.someData ?? [];
  }
}

The bug is that we expect foo to initially be someProperty, but someData may not yet be available and we end up setting [] as the value of foo on first render.

Since property assignment is non-reactive, we should warn of this bug, and suggest using @localCopy from https://github.com/tracked-tools/tracked-toolbox
so that changes to someProperty used in foo