Check primaries returned from libavif

Due to various double vs float arithmetic,
some primaries could be rejected by Qt.
If necessary, we adjust the values so they
will be accepted by Qt.

Remove newline from the ends of error strings.

src/imageformats/avif_p.h

@@ -14,6 +14,7 @@
 #include <qimageiohandler.h>
 #include <QImageIOPlugin>
 #include <QByteArray>
+#include <QPointF>
 #include <avif/avif.h>
 
 class QAVIFHandler : public QImageIOHandler
@@ -41,6 +42,7 @@ public:
 
   int loopCount() const override;
 private:
+  static QPointF CompatibleChromacity(qreal chrX, qreal chrY);
   bool ensureParsed() const;
   bool ensureDecoder();
   bool decode_one_frame();