net: wifi: shell: manual code formatting

Various manual code formatting adjustments, including:
- Wrapping lines in the `long_options` declaration to prevent them
  from extending too far to the right.
- Adding missing `{` and `}` in the `if` statement in
  `cmd_wifi_set_rts_threshold`.
- Aligning `SHELL_CMD_ARG` in `wifi_commands` with previous declarations.

Signed-off-by: Pisit Sawangvonganan <pisit@ndrsolution.com>