React Native accessibility fixes (#5825)

* Accessibility: Make the native toolbox item communicate that it is a button.

* Accessibility: If an item is toggled, mark it as selected for accessibility

* Accessibility: Make the toolbox a toolbar for accessibility

* Accessibility: Mark the bottom sheet as a menu for accessibility

* Fix typo, AccessibilityRole, not AccessibleRole

* Statement fix

* Appease the linter

* Fix linting errors for real this time

react/features/base/dialog/components/native/BottomSheet.js

@@ -84,6 +84,8 @@ class BottomSheet extends PureComponent<Props> {
 
         return (
             <SlidingView
+                accessibilityRole = 'menu'
+                accessibilityViewIsModal = { true }
                 onHide = { this.props.onCancel }
                 position = 'bottom'
                 show = { true }>

react/features/base/toolbox/components/ToolboxItem.native.js

@@ -41,7 +41,8 @@ export default class ToolboxItem extends AbstractToolboxItem<Props> {
             elementAfter,
             onClick,
             showLabel,
-            styles
+            styles,
+            toggled
         } = this.props;
 
         let children = this._renderIcon();
@@ -72,6 +73,8 @@ export default class ToolboxItem extends AbstractToolboxItem<Props> {
         return (
             <TouchableHighlight
                 accessibilityLabel = { this.accessibilityLabel }
+                accessibilityRole = 'button'
+                accessibilityState = {{ 'selected': toggled }}
                 disabled = { disabled }
                 onPress = { onClick }
                 style = { style }

react/features/toolbox/components/native/Toolbox.js

@@ -110,6 +110,7 @@ class Toolbox extends PureComponent<Props> {
 
         return (
             <View
+                accessibilityRole = 'toolbar'
                 pointerEvents = 'box-none'
                 style = { styles.toolbar }>
                 {