GUACAMOLE-630: Do not contain entire field nor entire header within <label>.

Enclosing the entire field within the <label> results in problems when
the field is large and when the field contains multiple interactive
elements. Clicking within interactive elements of a complex field
triggers the <label>, refocusing the first input element. If the field
is large, the <label> will contain empty space which also refocuses the
input field upon being clicked, despite appearing to be the background
of the page.

guacamole/src/main/webapp/app/form/templates/emailField.html

@@ -1,8 +1,9 @@
 <div class="email-field">
     <input type="email"
+           ng-attr-id="{{ fieldId }}"
            ng-model="model"
            ng-hide="readOnly"
            autocorrect="off"
            autocapitalize="off"/>
     <a href="mailto:{{model}}" ng-show="readOnly">{{model}}</a>
-</div>
+</div>