Misleading click feedback in complex md-nav-list

#### Bug, feature request, or proposal:

UX related bug

#### What is the expected behavior?

When the user clicks a link in a `md-list-item` inside a complex `md-nav-list`, the link should be activated

#### What is the current behavior?

When the user clicks the link **close to the edge**, she obtains the feedback (the ripple effect is fired) but the link does not get the click event

#### What are the steps to reproduce?

Use the template provided at https://material.angular.io/components/component/list#navigation-lists (_For more complex navigation lists..._) or visit http://plnkr.co/edit/oqGfqlDTYRLF4bOSHQGv?p=preview

Click at the edges of the elements of the list.

#### What is the use-case or motivation for changing an existing behavior?

An UX issue; users get the feedback when they click but the app does not fire the action

#### Which versions of Angular, Material, OS, TypeScript, browsers are affected?

Tested with Chromium 58.0.3029.81 and Firefox 45.9.0

#### Is there anything else we should know?

The following gif shows how the `mat-list-text` element (container of the `` element ) is smaller than the `mat-list-item` element. Therefore, it doesn't get the click event

Start with the complex navigation-list example in the Material list documentation or reproduce the behavior using the linked Plunker. Inspect the relationship between the md-list-item, mat-list-text container, and link at the list edges; done means clicking anywhere on the item activates the link consistently with the ripple feedback.

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