fix(ui5-dialog): improve accessibility (#1477)

Author: ilhan007

packages/main/src/Dialog.hbs

@@ -3,7 +3,7 @@
 <span class="ui5-popup-frame" @focusin="{{_onfocusin}}">
 	<span id="{{_id}}-firstfe" tabindex="0"></span>
 	<div style="{{zindex}}" class="ui5-dialog-root-parent {{classes.dialogParent}}">
-		<div tabindex="-1" aria-labelledby="{{headerAriaLabelledBy}}" role="dialog" aria-modal="true" class="ui5-popup-root ui5-dialog-root {{classes.dialogParent}}">
+		<section tabindex="-1" aria-labelledby="{{headerAriaLabelledBy}}" role="dialog" aria-modal="true" class="ui5-popup-root ui5-dialog-root {{classes.dialogParent}}">
 			{{> header}}
 			<section class="ui5-dialog-section">
 				<div class="ui5-popup-content">
@@ -13,7 +13,7 @@
 				</div>
 			</section>
 			{{> footer}}
-		</div>
+		</section>
 	</div>
 	<span id="{{_id}}-lastfe" tabindex="0"></span>
 	<div tabindex="0" id="{{_id}}-blocklayer" style="{{blockLayer}}" class="{{classes.blockLayer}}"></div>

packages/main/src/Popup.hbs

@@ -6,7 +6,7 @@
 					<slot name="header"></slot>
 				</div>
 			{{else}}
-				<h2 id="{{_id}}-popup-heading" role="{{role}}" class="ui5-popup-header ui5-popup-headerText">{{headerText}}</h2>
+				<h2 id="{{_id}}-popup-heading" class="ui5-popup-header ui5-popup-headerText">{{headerText}}</h2>
 			{{/if}}
 		</header>
 	{{/if}}
@@ -15,7 +15,7 @@
 {{#*inline "footer"}}
 	{{#if hasFooter}}
 		<footer>
-			<div class="ui5-popup-footer">
+			<div class="ui5-popup-footer" role="toolbar">
 				<slot name="footer"></slot>
 			</div>
 		</footer>