[AI-FSSDK] [FSSDK-12735] Add holdout exclude_targeted_deliveries support

[esrakartalOpt]

Summary

Adds support for the exclude_targeted_deliveries field on Holdout entities. When this flag is true, users bucketed into the holdout are still served Targeted Delivery (rollout) rules normally, while A/B Test and Multi-Armed Bandit experiments continue to respect the holdout.

Changes

• Added ExcludeTargetedDeliveries field to both datafile and domain Holdout entities with JSON deserialization
• Updated holdout mapper to propagate the new field from datafile to domain model
• Modified composite feature service to evaluate TD rules normally when a holdout has the exclusion flag set, while still blocking AB/MAB/CMAB experiments
• Added Holdout pointer to FeatureDecision so the composite service can inspect holdout properties after bucketing

Jira Ticket

FSSDK-12735