Fixes #38914 - Use ETag-aware patch_if_match for Redfish operations

[spesnova717]

Summary

Some Redfish implementations reject PATCH requests without If-Match.
This change updates boot device operations to use
patch_if_match, enabling ETag-based conditional PATCH when needed.

Problem

Certain BMC implementations require the If-Match header
with ETag values for PATCH operations.
The previous implementation using system.patch
did not include this header, causing operations to fail on some hardware.

Solution

Changed PATCH operations in modules/bmc/redfish.rb to use patch_if_match,
which automatically includes the If-Match header with the appropriate ETag value when available.

[spesnova717]

Hi @ekohl ,

redfish_client 0.8.0 has now been officially released with ETag support included.
I've updated the dependency to use the released 0.8.0 version instead of the forked branch.

Thank you as always for your review.

[stejskalleos]

🍏 LGTM

• Scope of introduced changes is clear and does what it should
• Well covered by the tests

My testing

This time, my testing abilities were limited to the redfishMockupServer.

curl --user admin:changeme \
  -X PUT \
  -H "Content-Type: application/json" \
  -d '{}' \
  "http://smart-proxy.local.lan/bmc/:redfish_host/chassis/config/bootdevice/pxe"

=>

{
  "action": "bios",
  "result": {
    "device": "bios",
    "reboot": null,
    "persistent": null
  }
}

and logs from the redfish mockup server:

"GET /redfish/v1/Systems/RackServer-3 HTTP/1.1"
   PATCH: Content: type=application/json and params={}
   PATCH: Data: {'Boot': {'BootSourceOverrideTarget': 'BiosSetup', 'BootSourceOverrideEnabled': 'Once'}}
application/json

The overall result looks good, and looking at the coverage in the redfish_client PR, I can say we can merge, even without tests on a real setup.

I'll keep the PR open until Monday to give the community time to comment. If there are no objections on Monday, I will merge the PR.

The requested change has been addressed.

[stejskalleos]

Thanks @spesnova717

[spesnova717]

Thanks @stejskalleos for the testing and for merging this!
I really appreciate the verification with the redfishMockupServer.