heif-enc --params does not show integer defaults

[bradh]

This is a placeholder, a bit more investigation required to fully scope the problem.

It looks like heif-enc actually shows the current value.

https://github.com/strukturag/libheif/blob/d9daff2e6e54cc21c3f01a9312af73f2cbd4c8f5/examples/heif_enc.cc#L227-L233 and https://github.com/strukturag/libheif/blob/d9daff2e6e54cc21c3f01a9312af73f2cbd4c8f5/libheif/heif.cc#L2297-L2302

It looks like at least x265 avoids showing default for one case, even though it does have a default:

https://github.com/strukturag/libheif/blob/d9daff2e6e54cc21c3f01a9312af73f2cbd4c8f5/libheif/plugins/encoder_x265.cc#L267