Fix #146057: Crash when using Convolve node with GPU

The Convolve node crashes Blender if used with GPU device and its output
is used multiple times. This is due to a use after free error, because
the convolve node ignored the reference count of the output.

To fix this, we retain the reference count of the output by stealing the
data of the GPU-side buffer, instead of overwriting the output with it.

Pull Request: https://projects.blender.org/blender/blender/pulls/146074

source/blender/compositor/algorithms/intern/convolve.cc

@@ -252,7 +252,8 @@ void convolve(Context &context,
   });
 
   if (context.use_gpu()) {
-    output = output_cpu.upload_to_gpu(true);
+    Result output_gpu = output_cpu.upload_to_gpu(true);
+    output.steal_data(output_gpu);
     output_cpu.release();
   }
   else {