logging cleanup of scheduler pkg

[nirrozenbaum]

What type of PR is this?
/kind cleanup

What this PR does / why we need it:
This PR is fixing few logging issues in the scheduling package.

1. scheduler is logging twice the same set of key value pairs.
   for example (request-id and targetModelName are logged twice):

{"level":"Level(-4)","ts":"2025-11-03T13:26:36Z","caller":"scheduling/scheduler.go:60","msg":"Running profile handler, Pick profiles","x-request-id":"35ca6232-5ed4-4f6a-9460-f08839e5c750","objectiveKey":"","incomingModelName":"meta-llama/Llama-3.1-8B-Instruct","targetModelName":"meta-llama/Llama-3.1-8B-Instruct","priority":0,"requestId":"35ca6232-5ed4-4f6a-9460-f08839e5c750","targetModel":"meta-llama/Llama-3.1-8B-Instruct","plugin":"single-profile-handler/single-profile-handler"}
{"level":"Level(-4)","ts":"2025-11-03T13:26:36Z","caller":"scheduling/scheduler.go:64","msg":"Completed running profile handler Pick profiles successfully","x-request-id":"35ca6232-5ed4-4f6a-9460-f08839e5c750","objectiveKey":"","incomingModelName":"meta-llama/Llama-3.1-8B-Instruct","targetModelName":"meta-llama/Llama-3.1-8B-Instruct","priority":0,"requestId":"35ca6232-5ed4-4f6a-9460-f08839e5c750","targetModel":"meta-llama/Llama-3.1-8B-Instruct","plugin":"single-profile-handler/single-profile-handler","result":{"default":{}}}

This is happening because the scheduler uses WithValues for values that were already added to the logger.

2. picker is trying to log a map and that appears as an unsupported type error in the log:

{"level":"Level(-4)","ts":"2025-11-03T11:54:46Z","caller":"framework/scheduler_profile.go:184","msg":"Running picker plugin","x-request-id":"95dbab2a-662a-4bfb-9596-0bcd314d49ae","objectiveKey":"","incomingModelName":"meta-llama/Llama-3.1-8B-Instruct","targetModelName":"meta-llama/Llama-3.1-8B-Instruct","priority":0,"plugin":"max-score-picker/max-score-picker","pods-weighted-scoreError":"json: unsupported type: map[types.Pod]float64"}

switched to using slice instead which should work as expected.

3. made minor tweaks to the log levels. log lines that print potentially enormous amount of data are using log level 4 (e.g., candidate pods, selected pods, scores per pod). log lines that are printed once per request handling process are using log level 3.

Which issue(s) this PR fixes:

Fixes #

Does this PR introduce a user-facing change?:

None

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[kfswain]

/lgtm
/approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: kfswain, nirrozenbaum

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