fix: add accessibilityLabel prop to back button

fixes #6895

packages/stack/src/types.tsx

@@ -404,6 +404,10 @@ export type StackHeaderLeftButtonProps = {
    * Whether it's possible to navigate back in stack.
    */
   canGoBack?: boolean;
+  /**
+   * Accessibility label for the button for screen readers.
+   */
+  accessibilityLabel?: string;
 };
 
 export type StackHeaderTitleProps = {

packages/stack/src/views/Header/HeaderBackButton.tsx

@@ -29,6 +29,7 @@ export default function HeaderBackButton({
   tintColor: customTintColor,
   titleLayout,
   truncatedLabel = 'Back',
+  accessibilityLabel = label && label !== 'Back' ? `${label}, back` : 'Go back',
 }: Props) {
   const { dark, colors } = useTheme();
 
@@ -153,9 +154,7 @@ export default function HeaderBackButton({
       accessible
       accessibilityRole="button"
       accessibilityComponentType="button"
-      accessibilityLabel={
-        label && label !== 'Back' ? `${label}, back` : 'Go back'
-      }
+      accessibilityLabel={accessibilityLabel}
       accessibilityTraits="button"
       testID="header-back"
       delayPressIn={0}