RHEL-9.0 still has old osname redhat in raw images

[mcattamoredhat]

In #7818 it has been seen that RHEL-9.0 still has old osname redhat in edge deployment.

This issue affects following test cases:

edge-fdo-aio-9.0
edge-raw-image-9.0
edge-simplified-installer-9.0

[mcattamoredhat]

edge-raw-image-90 error log

TASK [check /var mount point] **************************************************
changed: [192.168.100.50] => changed=true 
  cmd:
  - findmnt
  - -r
  - -o
  - SOURCE
  - -n
  - /var
  delta: '0:00:00.004066'
  end: '2024-06-10 04:35:18.132913'
  msg: ''
  rc: 0
  start: '2024-06-10 04:35:18.128847'
  stderr: ''
  stderr_lines: <omitted>
  stdout: /dev/mapper/luks-99095621-f5b7-4f7c-8822-078fc3598769[/ostree/deploy/redhat/var]
  stdout_lines: <omitted>

TASK [assert] ******************************************************************
fatal: [192.168.100.50]: FAILED! => changed=false 
  assertion: result_var_mount_point.stdout == "/dev/mapper/luks-99095621-f5b7-4f7c-8822-078fc3598769[/ostree/deploy/rhel-edge/var]"
  evaluated_to: false
  msg: /var does not mount on /dev/mapper/luks-99095621-f5b7-4f7c-8822-078fc3598769[/ostree/deploy/rhel-edge/var]