With horizontal listbox, first chip gets focused on parent wrapper click

#### What is the expected behavior?
".mat-chip-list-wrapper" should not catch click event

#### What is the current behavior?
When you click outside of the chips in the ".mat-chip-list-wrapper" container that is full width due to flex property, the first chip of the wrapper get selected.

#### What are the steps to reproduce?
Use the official chips example https://odjogmnnjkj.angular.stackblitz.io/ and click on the far right of the chips. The first chip will get focused.

#### Which versions of Angular, Material, OS, TypeScript, browsers are affected?
Angular 7.2.12, Material 7.3.6, Typescript 3.1.1
Issue found on:
- mac OS High Sierra with Chrome 73.0.3683.86, Safari 12.1, Firefox
- windows 10 enterprise using Chrome 73.0.3683.103, Edge and Firefox 60.6.1esr

Start with the official chips example and reproduce the click in the empty space of the full-width .mat-chip-list-wrapper. Trace the wrapper's click and focus behavior, then verify that clicking outside the chips no longer focuses the first chip while clicking a chip still works.

Written by the indexing model from the issue text.