title: patchValue to set value and disable the field
body: <p>I'm pushing a FormArray with some values, and i need to dynamically set disabled property in certain fields after i've loaded a list.
  My question is: IS there a way to set the value and set the disabled property using only patchValue?</p>
  
  <p>I've tried something like  this.rowArray.controls[index].patchvalue({format: "NUMBER", disabled:true}) but it doesn't seem to work.</p>
  
  <pre><code>  this.rowList.forEach((el, index) =&gt; {
                this.rowArray.push(
                  this.fb.group(
                    {
                      name: new FormControl(el.name, [
                        Validators.required,
                        Validators.maxLength(30),
                        Validators.pattern(this.BAN_SPECIAL_BUT_UNDERSCORE)
                      ]),
                      source: new FormControl(el.source, Validators.required)
  .....
  </code></pre>
  
  <p>and after that </p>
  
  <pre><code>    if (this.rowArray.controls[index].get("source").value === "CSV") {
                  this.rowArray.controls[index].patchValue({
                    format: "NUMBER",
                    disabled: true
                  });
                }
  </code></pre>
  
  <p>rowList is my matrix that comes from backEnd.</p>