Some stateful PA attributes cannot be refreshed in reconcile

[kr11]

🐛 Describe the bug

Related to #406 and #409

We discovered that some parameters in KPA are stateful, such as the three parts of KPAScaler: panic_window, stable_window, and delay_windows. These three parts are initialized in newReconciler only once, and won't be changed in reconcile.

The reconcile() function updates the KpaScalingContext periodically but does not refresh these three parts. As a result, apply -f pa.yaml may fail to take effect on these stateful parameters.

Let's think a complex situation:

1. Bob creates KPA with stable_duration of 30s. So controller will maintain the past 30s metrics.
2. Bob changes the kpa.yaml by setting stable_duration to 10s and apply it again, should controller discard the extra metrics?
3. Bob reset stable_duration to 60s, and so on...

Steps to Reproduce

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Expected behavior

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Environment

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