avifpng.c: support ImageMagick app1 exif text data (#2700)

ImageMagick 6.9.13-12 uses lowercase app1 in the raw profile string.

Author: jzern

apps/shared/avifpng.c

@@ -173,7 +173,7 @@ static avifBool avifExtractExifAndXMP(png_structp png, png_infop info, avifBool
             }
             avifRemoveHeader(&xmpApp1Header, &avif->xmp); // Ignore the return value because the header is optional.
             *ignoreXMP = AVIF_TRUE;                       // Ignore any other XMP chunk.
-        } else if (!strcmp(text->key, "Raw profile type APP1")) {
+        } else if (!strcmp(text->key, "Raw profile type APP1") || !strcmp(text->key, "Raw profile type app1")) { // ImageMagick uses lowercase app1.
             // This can be either Exif, XMP or something else.
             avifRWData metadata = { NULL, 0 };
             if (!avifCopyRawProfile(text->text, textLength, &metadata)) {