Accessibility updates (#19561)

* Announce full screen mode to screen reader, use extra helpful text in panel title input

* Update jest snapshots

* See if removing full sceen mode aria label fixes snapshot test on jenkins.

* Bring back EuiScreenReadyOnly to confirm it is breaking snapshot tests

* Try updating baselines with slightly larger width for the screen

* Move screenready to external, non styled div, go back to original browser size and snapshots

* update snaphots

src/core_plugins/kibana/public/dashboard/components/__snapshots__/exit_full_screen_button.test.js.snap

@@ -1,33 +1,41 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
 exports[`is rendered 1`] = `
-<div
-  class="exitFullScreenButton"
->
-  <button
-    aria-label="Exit full screen mode"
-    class="kuiButton exitFullScreenMode"
-    type="hollow"
+<div>
+  <p
+    aria-live="polite"
+    class="euiScreenReaderOnly"
   >
-    <span
-      class="kuiButton__inner"
+    In full screen mode, press ESC to exit.
+  </p>
+  <div
+    class="exitFullScreenButton"
+  >
+    <button
+      aria-label="Exit full screen mode"
+      class="kuiButton exitFullScreenMode"
+      type="hollow"
     >
-      <span>
-        <span
-          class="exitFullScreenModeLogo"
-          data-test-subj="exitFullScreenModeLogo"
-        />
-        <span
-          class="exitFullScreenModeText"
-          data-test-subj="exitFullScreenModeText"
-        >
-          Exit full screen
+      <span
+        class="kuiButton__inner"
+      >
+        <span>
           <span
-            class="kuiIcon fa fa-angle-left"
+            class="exitFullScreenModeLogo"
+            data-test-subj="exitFullScreenModeLogo"
           />
+          <span
+            class="exitFullScreenModeText"
+            data-test-subj="exitFullScreenModeText"
+          >
+            Exit full screen
+            <span
+              class="kuiIcon fa fa-angle-left"
+            />
+          </span>
         </span>
       </span>
-    </span>
-  </button>
+    </button>
+  </div>
 </div>
 `;

src/core_plugins/kibana/public/dashboard/components/exit_full_screen_button.js

@@ -27,6 +27,7 @@ import {
 
 import {
   keyCodes,
+  EuiScreenReaderOnly,
 } from '@elastic/eui';
 
 export class ExitFullScreenButton extends PureComponent {
@@ -49,21 +50,28 @@ export class ExitFullScreenButton extends PureComponent {
 
   render() {
     return (
-      <div
-        className="exitFullScreenButton"
-      >
-        <KuiButton
-          type="hollow"
-          aria-label="Exit full screen mode"
-          className="exitFullScreenMode"
-          onClick={this.props.onExitFullScreenMode}
+      <div>
+        <EuiScreenReaderOnly>
+          <p aria-live="polite">
+            In full screen mode, press ESC to exit.
+          </p>
+        </EuiScreenReaderOnly>
+        <div
+          className="exitFullScreenButton"
         >
-          <span className="exitFullScreenModeLogo" data-test-subj="exitFullScreenModeLogo"/>
-          <span className="exitFullScreenModeText" data-test-subj="exitFullScreenModeText">
-            Exit full screen
-            <span className="kuiIcon fa fa-angle-left"/>
-          </span>
-        </KuiButton>
+          <KuiButton
+            type="hollow"
+            aria-label="Exit full screen mode"
+            className="exitFullScreenMode"
+            onClick={this.props.onExitFullScreenMode}
+          >
+            <span className="exitFullScreenModeLogo" data-test-subj="exitFullScreenModeLogo"/>
+            <span className="exitFullScreenModeText" data-test-subj="exitFullScreenModeText">
+              Exit full screen
+              <span className="kuiIcon fa fa-angle-left"/>
+            </span>
+          </KuiButton>
+        </div>
       </div>
     );
   }

src/core_plugins/kibana/public/dashboard/panel/panel_header/panel_options_menu_form.js

@@ -54,6 +54,7 @@ export function PanelOptionsMenuForm({ title, onReset, onUpdatePanelTitle, onClo
         value={title}
         onChange={onInputChange}
         onKeyDown={onKeyDown}
+        aria-label="Changes to this input are applied immediately. Press enter to exit."
       />
       <KuiButton
         buttonType="hollow"