Fix Chromevox auto alt implementation.

Missed changing function name in one place, in
https://chromium-review.googlesource.com/c/1480542.

Bug: 905419
Change-Id: I38c174a4899b163c58ebc99ff0fd995fb7c6c9b5
Reviewed-on: https://chromium-review.googlesource.com/c/1484580Reviewed-by: David Tseng <dtseng@chromium.org>
Commit-Queue: Katie Dektar <katie@chromium.org>
Auto-Submit: Katie Dektar <katie@chromium.org>
Cr-Commit-Position: refs/heads/master@{#635171}

chrome/renderer/resources/extensions/automation/automation_node.js

@@ -1567,7 +1567,7 @@ utils.expose(AutomationNode, AutomationNodeImpl, {
         'restriction',
         'state',
         'location',
-        'imageAnnotationStatus',
+        'imageAnnotation',
         'indexInParent',
         'lineStartOffsets',
         'root',