Move redaction to pii guardrails as a parameter

[VisargD]

Instead of redaction being handled by a separate hook type (mutator), it should be moved as a parameter to the existing guardrail hook type. If the redact flag is true, then the handler will redact and update the context of the HookSpan. There are a few reasons to do this:

• Integrations like Bedrock allow you to configure multiple checks (such as word filters, content filters, and PII redaction) within a single guardrail. If redaction was a separate hook, it would require two separate guardrails (one for redaction and one for other checks), which could feel a bit redundant. This is just one example, and there could be many more use cases where this becomes a problem in the future.