bmcweb: Revert to old sensor override logic
See github.com/openbmc/bmcweb/issues/253 for technical details.
This reverts the following commits:
* 3e35c761b7793696267870550bd6f0b0035f4110
* c71d61258bd3cd8573166011b450a1eecce2c572
Tested: Meltan fan diag passes.
```
./blaze-bin/third_party/meltan/diagnostics/servers/fan_speed/fan_speed \
    --hwinterface_default_backend=redfish \
    --hwinterface_target_address=localhost \
    --hwinterface_target_port=1234
...
{
    "testRunArtifact": {
        "testRunEnd": {
            "name": "fan_speed",
            "status": "COMPLETE",
            "result": "PASS"
        }
    },
    "sequenceNumber": 252,
    "timestamp": "2023-05-25T22:14:36.210811Z"
}
```
Google-Bug-Id: 277958097
Google-Bug-Id: 283748401
Change-Id: Ifd7d5bcb11015d73cf75eca1f50d1d9ff75447ac
Signed-off-by: Vlad Sytchenko <vsytch@google.com>
2 files changed