tools: ynl: cli: print reply in combined format if possible

tools: ynl: cli: print reply in combined format if possible

As pointed out during review of the --list-attrs support the GET
ops very often return the same attrs from do and dump. Make the
output more readable by combining the reply information, from:

  Do request attributes:
    - ifindex: u32
      netdev ifindex

  Do reply attributes:
    - ifindex: u32
      netdev ifindex
    [ .. other attrs .. ]

  Dump reply attributes:
    - ifindex: u32
      netdev ifindex
    [ .. other attrs .. ]

To, after:

  Do request attributes:
    - ifindex: u32
      netdev ifindex

  Do and Dump reply attributes:
    - ifindex: u32
      netdev ifindex
    [ .. other attrs .. ]

Tested-by: Gal Pressman <gal@nvidia.com>
Acked-by: Stanislav Fomichev <sdf@fomichev.me>
Reviewed-by: Donald Hunter <donald.hunter@gmail.com>
Link: https://patch.msgid.link/20260110233142.3921386-8-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>