Fix the problem that AccessibilityNodeInfo maybe null and cause a crash.

If the mAccessibilityDelegate of a view is not null, the mAccessibilityDelegate also has a corresponding AccessibilityNodeProvider object. If the AccessibilityNodeProvider does not overload the createAccessibilityNodeInfo(int virtualViewId) method, the app will crash. This bugfix is to add a non-null judgment here.

Bug:285078234

Change-Id: Iaccca83e9e47cfeb271186d0a4344555d6b433b6
Signed-off-by: liangguihao1 <liangguihao1@xiaomi.corp-partner.google.com>