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/checkboxField.html

@@ -1 +1,5 @@
-<input type="checkbox" ng-model="typedValue" autocorrect="off" autocapitalize="off"/>
+<input type="checkbox"
+       ng-attr-id="{{ fieldId }}"
+       ng-model="typedValue"
+       autocorrect="off"
+       autocapitalize="off"/>