Check zero width/height in avifRGBImageSetDefaults

XANOY (https://github.com/X-ANOY) reported the bug and suggested the
fix.

Fixes https://github.com/AOMediaCodec/libavif/issues/2985.

src/avif.c

diff --git a/src/avif.c b/src/avif.c
index 93bd1b1..d6588be 100644
--- a/src/avif.c
+++ b/src/avif.c
@@ -715,6 +715,9 @@
 avifResult avifRGBImageAllocatePixels(avifRGBImage * rgb)
 {
     avifRGBImageFreePixels(rgb);
+    if (rgb->width == 0 || rgb->height == 0) {
+        return AVIF_RESULT_INVALID_ARGUMENT;
+    }
     const uint32_t pixelSize = avifRGBImagePixelSize(rgb);
     if (rgb->width > UINT32_MAX / pixelSize) {
         return AVIF_RESULT_INVALID_ARGUMENT;

tests/gtest/avifrgbtoyuvtest.cc

diff --git a/tests/gtest/avifrgbtoyuvtest.cc b/tests/gtest/avifrgbtoyuvtest.cc
index 2544bc5..1ab22dd 100644
--- a/tests/gtest/avifrgbtoyuvtest.cc
+++ b/tests/gtest/avifrgbtoyuvtest.cc
@@ -3,6 +3,7 @@
 
 #include <algorithm>
 #include <cmath>
+#include <cstring>
 #include <memory>
 #include <tuple>
 
@@ -499,6 +500,26 @@
   }
 }
 
+TEST(RGBToYUVTest, ZeroWidthOrHeight) {
+  avifRGBImage rgb;
+  memset(&rgb, 0, sizeof(rgb));
+  rgb.depth = 8;
+  rgb.format = AVIF_RGB_FORMAT_RGB;
+
+  rgb.width = 0;
+  rgb.height = 1;
+  EXPECT_EQ(avifRGBImageAllocatePixels(&rgb), AVIF_RESULT_INVALID_ARGUMENT);
+
+  rgb.width = 1;
+  rgb.height = 0;
+  EXPECT_EQ(avifRGBImageAllocatePixels(&rgb), AVIF_RESULT_INVALID_ARGUMENT);
+
+  rgb.width = 1;
+  rgb.height = 1;
+  EXPECT_EQ(avifRGBImageAllocatePixels(&rgb), AVIF_RESULT_OK);
+  avifRGBImageFreePixels(&rgb);
+}
+
 //------------------------------------------------------------------------------
 // Selected configurations