docs(material/datepicker): remove width from example (#17866)

In date picker the events example is not responsive on mobile due to this added `width`

Author: ajitsinghkaler

src/components-examples/material/datepicker/datepicker-events/datepicker-events-example.css

@@ -1,5 +1,4 @@
 .example-events {
-  width: 400px;
   height: 200px;
   border: 1px solid #555;
   overflow: auto;