<!-- Describe your changes in detail -->

Enhanced Pix payment support for Adyen connector with two changes:

1. **Expiry Date Support**: Added `expiry_date` field to `BankTransferData::Pix` variant in API and domain models and mapped it to Adyen's `sessionValidity`
2. **CPF/CNPJ Mapping**: Map CPF or CNPJ from Pix payment data to Adyen's `socialSecurityNumber` field
To implement this **payment** feature, you'll need to modify these architectural layers:


**1. API Request/Response Models**
   - `crates/api_models/src/payments.rs`
   - `crates/api_models/src/payments/additional_info.rs`

**2. Domain Models (Business Logic Types)**
   - `crates/hyperswitch_domain_models/src/payment_method_data.rs`

**3. External Connector Integration**
   - `crates/hyperswitch_connectors/src/connectors/adyen/transformers.rs`

**4. Other**
   - `api-reference/v1/openapi_spec_v1.json`
   - `api-reference/v2/openapi_spec_v2.json`

**Code Patterns Applied:**
- Extend existing types with new fields (15 changes)
- Add conditional logic for feature flags or filtering (2 changes)

**Detailed Identifier Changes:**


Commit 9bf1e95f:
Files to modify:


**crates/api_models/src/payments.rs**
  Modify existing code

**crates/api_models/src/payments/additional_info.rs**
  Modify existing code

**crates/hyperswitch_connectors/src/connectors/adyen/transformers.rs**
  Modify existing code

**crates/hyperswitch_domain_models/src/payment_method_data.rs**
  Modify existing code
{"pr_number": 8702, "pr_title": "refactor(connector): [Adyen] map ssn and session validity for Pix", "merged_at": "2025-07-22T10:15:12Z", "intent": {"feature_type": "payment", "action": "add_feature", "entities": ["customer", "payment", "merchant"]}, "hierarchy": {"api_models": ["crates/api_models/src/payments.rs", "crates/api_models/src/payments/additional_info.rs"], "domain": ["crates/hyperswitch_domain_models/src/payment_method_data.rs"], "connectors": ["crates/hyperswitch_connectors/src/connectors/adyen/transformers.rs"], "other": ["api-reference/v1/openapi_spec_v1.json", "api-reference/v2/openapi_spec_v2.json"]}, "change_types": {"fields_added": 15, "conditionals_added": 2}, "has_identifier_data": true, "commits_matched": 1, "match_method": "pr_number"}