Add grub package to seedimage built in OBS

[frelon]

Getting the following error when building a raw disk image using a seedimage-builder from dev:

DEBU[2023-11-23T14:06:30Z] Running cmd: 'grub2-editenv /iso/build/oem/grubenv set next_entry=recovery'
ERRO[2023-11-23T14:06:30Z] Error running command: exec: "grub2-editenv": executable file not found in $PATH
ERRO[2023-11-23T14:06:30Z] Failed setting grub variables:
ERRO[2023-11-23T14:06:30Z] failed setting firstboot menu entry: exec: "grub2-editenv": executable file not found in $PATH
ERRO[2023-11-23T14:06:30Z] Woophs, something went terribly wrong: 1 error occurred:
        * exec: "grub2-editenv": executable file not found in $PATH

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (20ce1e0) 54.13% compared to head (fb14982) 54.13%.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #568   +/-   ##
=======================================
  Coverage   54.13%   54.13%           
=======================================
  Files          39       39           
  Lines        6005     6005           
=======================================
  Hits         3251     3251           
  Misses       2472     2472           
  Partials      282      282           

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[davidcassany]

LGTM