title: Disabled is not working in Angular reactive forms
body: <p>I am trying to use <code>disabled</code> on a material form input : </p>
  
  <pre><code>&lt;mat-form-field&gt;
    &lt;input 
      matInput 
      formControlName="date" 
      [matDatepicker]="dp3" 
      placeholder="YYYY-MM-DD"&gt;
    &lt;mat-datepicker-toggle 
      matSuffix 
      [for]="dp3"&gt;
    &lt;/mat-datepicker-toggle&gt;
    &lt;mat-datepicker #dp3 disabled="false"&gt;&lt;/mat-datepicker&gt;
  &lt;/mat-form-field&gt;
  </code></pre>
  
  <p>My form control is defined as follow: </p>
  
  <pre><code>this.dateAmountFormGroup = this.fb.group({
    date: new FormControl({
      value: '',
      disabled: true
    }),
  });
  </code></pre>
  
  <p>However, when clicking on the <code>input</code> field, it is not getting <strong>disabled</strong>. </p>