[Mellanox] Change the default breakout mode for internal ports of the Mellanox-SN4700-O28 SKU.

[oleksandrivantsiv]

Why I did it

Fix the issue with configuration generation from the minigrapth:

root@sonic:/home/admin# config load_minigraph -y
Disabling container monitoring ...
Stopping SONiC target ...
Running command: /usr/local/bin/sonic-cfggen -H -m -j /etc/sonic/init_cfg.json --write-to-db
Traceback (most recent call last):
  File "/usr/local/bin/sonic-cfggen", line 452, in <module>
    main()
  File "/usr/local/bin/sonic-cfggen", line 342, in main
    deep_update(data, parse_xml(minigraph, platform, asic_name=asic_name))
  File "/usr/local/lib/python3.9/dist-packages/minigraph.py", line 1542, in parse_xml
    (ports, alias_map, alias_asic_map) = get_port_config(hwsku=hwsku, platform=platform, port_config_file=port_config_file, asic_name=asic_name, hwsku_config_file=hwsku_config_file)
  File "/usr/local/lib/python3.9/dist-packages/portconfig.py", line 207, in get_port_config
    return parse_platform_json_file(hwsku_json_file, port_config_file)
  File "/usr/local/lib/python3.9/dist-packages/portconfig.py", line 422, in parse_platform_json_file
    child_ports = get_child_ports(intf, brkout_mode, platform_json_file)
  File "/usr/local/lib/python3.9/dist-packages/portconfig.py", line 395, in get_child_ports
    mode_handler = BreakoutCfg(interface, breakout_mode, port_dict[INTF_KEY][interface])
  File "/usr/local/lib/python3.9/dist-packages/portconfig.py", line 323, in __init__
    raise RuntimeError("Unsupported breakout mode {}!".format(bmode))
RuntimeError: Unsupported breakout mode 1x200G!

Work item tracking

• Microsoft ADO (number only):

How I did it

Change the default breakout mode for internal ports to the mode that corresponds platfom.json configuration.

How to verify it

• Deploy minigraph
• Run config load_minigraph -y command

Which release branch to backport (provide reason below if selected)

• 201811
• 201911
• 202006
• 202012
• 202106
• 202111
• 202205
• 202211
• 202305

Tested branch (Please provide the tested image version)

Description for the changelog

Link to config_db schema for YANG module changes

A picture of a cute animal (not mandatory but encouraged)