Vulkan: Suppress layered FB validation error.

This is popping up with a new roll of the VVL. Instead of fixing it,
we can disable it for now.

Bug: angleproject:6293
Change-Id: I6cd12a24b26a4f536db16631e198317e8c4d9fcc
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/3103505
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Commit-Queue: Jamie Madill <jmadill@chromium.org>

src/libANGLE/renderer/vulkan/RendererVk.cpp

@@ -183,6 +183,8 @@ constexpr const char *kSkippedMessages[] = {
     "VUID-VkImageViewCreateInfo-pNext-01585",
     // https://anglebug.com/6262
     "VUID-vkCmdClearAttachments-baseArrayLayer-00018",
+    // http://anglebug.com/6293
+    "VUID-VkFramebufferCreateInfo-flags-04535",
 };
 
 // Suppress validation errors that are known