fix(material-experimental/mdc-form-field): fix height for form field with textarea (#22089)

(cherry picked from commit a219a4a)

Author: annieyw

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

@@ -50,6 +50,9 @@
 // that the projected form-field control and content can stretch as needed, but we also
 // apply a default infix width to make the form-field's look natural.
 .mat-mdc-form-field-infix {
+  // Prevent extra height from being added around the textarea, which throws off the overall
+  // height of the form-field
+  line-height: 0;
   flex: auto;
   min-width: 0;
   width: $mat-form-field-default-infix-width;