Described in #6941 

This PR adds NTI flow integrations for below connectors

- Fiuu - store NTI ID in `payment_methods` from connector's PSync response
- Novalnet - use NTI ID for card payments
- Worldpay - store and use NTI ID for card payments
To implement this **search_filter** feature, you'll need to modify these architectural layers:


**1. External Connector Integration**
   - `crates/hyperswitch_connectors/src/connectors/fiuu.rs`
   - `crates/hyperswitch_connectors/src/connectors/fiuu/transformers.rs`
   - `crates/hyperswitch_connectors/src/connectors/novalnet/transformers.rs`
   - ... and 6 more files

**2. Tests**
   - `config/deployments/integration_test.toml`
   - `cypress-tests/cypress/e2e/PaymentUtils/Fiuu.js`
   - `cypress-tests/cypress/e2e/PaymentUtils/Novalnet.js`
   - ... and 2 more files

**3. Configuration Files**
   - `config/config.example.toml`
   - `config/deployments/sandbox.toml`
   - `config/development.toml`
   - ... and 2 more files

**Code Patterns Applied:**
- Define new data structures (3 changes)
- Implement new functions (15 changes)
- Extend existing types with new fields (171 changes)
- Add conditional logic for feature flags or filtering (1 changes)

**Detailed Identifier Changes:**


Commit d6b06605:
Files to modify:


**crates/hyperswitch_connectors/src/connectors/fiuu.rs**
  Modify existing code

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

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

**crates/hyperswitch_connectors/src/connectors/worldpay.rs**
  Modify existing code

**crates/hyperswitch_connectors/src/connectors/worldpay/requests.rs**
  Modify existing code

**crates/hyperswitch_connectors/src/connectors/worldpay/response.rs**
  Modify existing code

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

**crates/hyperswitch_connectors/src/utils.rs**
  Modify existing code

**crates/router/src/configs/defaults/payment_connector_required_fields.rs**
  Modify existing code
{"pr_number": 6946, "pr_title": "feat(connectors): fiuu,novalnet,worldpay - extend NTI flows", "merged_at": "2025-01-21T08:42:05Z", "intent": {"feature_type": "search_filter", "action": "add_feature", "entities": ["customer", "payment", "merchant"]}, "hierarchy": {"connectors": ["crates/hyperswitch_connectors/src/connectors/fiuu.rs", "crates/hyperswitch_connectors/src/connectors/fiuu/transformers.rs", "crates/hyperswitch_connectors/src/connectors/novalnet/transformers.rs", "crates/hyperswitch_connectors/src/connectors/worldpay.rs", "crates/hyperswitch_connectors/src/connectors/worldpay/requests.rs", "crates/hyperswitch_connectors/src/connectors/worldpay/response.rs", "crates/hyperswitch_connectors/src/connectors/worldpay/transformers.rs", "crates/hyperswitch_connectors/src/utils.rs", "crates/router/src/configs/defaults/payment_connector_required_fields.rs"], "tests": ["config/deployments/integration_test.toml", "cypress-tests/cypress/e2e/PaymentUtils/Fiuu.js", "cypress-tests/cypress/e2e/PaymentUtils/Novalnet.js", "cypress-tests/cypress/e2e/PaymentUtils/WorldPay.js", "loadtest/config/development.toml"], "config": ["config/config.example.toml", "config/deployments/sandbox.toml", "config/development.toml", "config/docker_compose.toml", "crates/router/locales/en.yml"]}, "change_types": {"structs_added": 3, "functions_added": 15, "fields_added": 171, "conditionals_added": 1}, "has_identifier_data": true, "commits_matched": 1, "match_method": "pr_number"}