fix(material-experimental/form-field): add filled MDC text field class

Author: asyncLiz

package.json

@@ -58,7 +58,7 @@
     "@types/youtube": "^0.0.38",
     "@webcomponents/custom-elements": "^1.1.0",
     "core-js": "^2.6.9",
-    "material-components-web": "6.0.0-canary.927fa902c.0",
+    "material-components-web": "6.0.0-canary.c4b4bba96.0",
     "rxjs": "^6.5.3",
     "systemjs": "0.19.43",
     "tslib": "^1.10.0",

src/material-experimental/mdc-form-field/form-field.html

@@ -33,6 +33,7 @@
 </ng-template>
 
 <div class="mat-mdc-text-field-wrapper mdc-text-field" #textField
+     [class.mdc-text-field--filled]="!_hasOutline()"
      [class.mdc-text-field--outlined]="_hasOutline()"
      [class.mdc-text-field--no-label]="!_hasFloatingLabel()"
      [class.mdc-text-field--disabled]="_control.disabled"