APIProperties serialization missing field

The field APIProperties::rgpCapture was added years ago but
renderdoc_serialize.inl wasn't updated. One of those edge cases
where the size check failed to flag the oversight due to the
field appearing prior to other subsequent (conditional) fields.
End result is that the RGP Capture menu option is always disabled,
even when the target supports it.

renderdoc/replay/renderdoc_serialise.inl

@@ -494,6 +494,7 @@ void DoSerialise(SerialiserType &ser, APIProperties &el)
 
   SERIALISE_MEMBER(shaderDebugging);
   SERIALISE_MEMBER(pixelHistory);
+  SERIALISE_MEMBER(rgpCapture);
 
   SERIALISE_MEMBER(ShaderLinkage);
   SERIALISE_MEMBER(YUVTextures);