Fix GN include checks

Author: ShabbyX

BUILD.gn

@@ -57,6 +57,7 @@ source_set("vulkan_headers") {
     "include/vulkan/vulkan_core.h",
     "include/vulkan/vulkan_screen.h",
     "include/vk_video/vulkan_video_codec_av1std_decode.h",
+    "include/vk_video/vulkan_video_codec_av1std_encode.h",
     "include/vk_video/vulkan_video_codec_av1std.h",
     "include/vk_video/vulkan_video_codec_h264std_decode.h",
     "include/vk_video/vulkan_video_codec_h264std_encode.h",