Add azp claim support within nested act/sub claim structures

[Bin4yi]

Problem

The azp (authorized party) claim is not properly handled in nested delegation chains:

• Loss of authorized party information in multi-level delegations
• Cannot track which client was originally authorized at each delegation level
• Compliance and audit trails are incomplete
• Difficult to determine authorization scope at each hop
• Security decisions cannot account for the full authorization context

Proposed Solution

Implement comprehensive azp claim support in nested structures:

• Embed azp claim within each level of nested act/sub claims
• Preserve azp through the entire delegation chain
• Add validation for azp claim consistency
• Update JWT claim processing to handle azp in nested contexts
• PRRA: Add Support nested act claim with azp and multi-audience in token request wso2-extensions/identity-inbound-auth-oauth#3028

Alternatives

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Version

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Developer Checklist

• [Behavioural Change] Does this change introduce a behavioral change to the product?
•  ↳ Approved by team lead
•  ↳ Label impact/behavioral-change added
• [Migration Impact] Does this change have a migration impact?
•  ↳ Migration label added (e.g., 7.2.0-migration)
•  ↳ Migration issues created and linked
• [New Configuration] Does this change introduce a new configuration?
•  ↳ Label config added
•  ↳ Configuration is properly documented