fix(material/select): use flexible overlay dimensions

Author: andrewseguin

src/material/select/select.html

@@ -39,6 +39,7 @@
   [cdkConnectedOverlayOrigin]="_preferredOverlayOrigin || fallbackOverlayOrigin"
   [cdkConnectedOverlayPositions]="_positions"
   [cdkConnectedOverlayWidth]="_overlayWidth"
+  [cdkConnectedOverlayFlexibleDimensions]="true"
   (backdropClick)="close()"
   (overlayKeydown)="_handleOverlayKeydown($event)">
   <div