Retrieves all conditional rules for a given Invoice.

{  "rules": [    {      "conditional_rule_id": "CR-11FF-A725-27C6999C-A699-33CD614E75ED",      "conditional_rule_type": "EARLY_PAYMENT_DISCOUNT",      "conditional_rule_value_type": "PERCENT",      "conditional_rule_value": "5",      "rule_expiry_terms": {        "rule_expiry_condition": "SEVEN_DAYS_AFTER_ISSUE_DATE",        "condition_rule_end_date": "2025-03-12"      },      "created_time": "2025-01-29T10:15:30Z",      "updated_time": "2025-01-29T10:15:30Z",      "links": [        {          "href": "/v2/invoicing/invoices/INV2-S884-EJT6-73AU-QF4C/conditional-rules/CR-11FF-A725-27C6999C-A699-33CD614E75ED",          "rel": "self",          "method": "GET"        },        {          "rel": "self",          "href": "https://api.paypal.com/v2/invoicing/invoices/INV2-S884-EJT6-73AU-QF4C",          "method": "GET"        },        {          "href": "/v2/invoicing/invoices/INV2-S884-EJT6-73AU-QF4C/conditional-rules/CR-11FF-A725-27C6999C-A699-33CD614E75ED",          "rel": "update",          "method": "PUT"        },        {          "href": "/v2/invoicing/invoices/INV2-S884-EJT6-73AU-QF4C/conditional-rules/CR-11FF-A725-27C6999C-A699-33CD614E75ED",          "rel": "delete",          "method": "DELETE"        }      ]    },    {      "conditional_rule_id": "CR-11FF-A725-27C6999C-A699-33CD614E75EC",      "conditional_rule_type": "AUTO_CANCEL",      "rule_expiry_terms": {        "rule_expiry_condition": "SPECIFIC_DATE",        "condition_rule_end_date": "2025-03-12"      },      "created_time": "2025-01-29T10:15:30Z",      "updated_time": "2025-01-29T10:15:30Z",      "links": [        {          "href": "/v2/invoicing/invoices/INV2-S884-EJT6-73AU-QF4C/conditional-rules/CR-11FF-A725-27C6999C-A699-33CD614E75EC",          "rel": "self",          "method": "GET"        },        {          "href": "/v2/invoicing/invoices/INV2-S884-EJT6-73AU-QF4C/conditional-rules/CR-11FF-A725-27C6999C-A699-33CD614E75EC",          "rel": "update",          "method": "PUT"        },        {          "href": "/v2/invoicing/invoices/INV2-S884-EJT6-73AU-QF4C/conditional-rules/CR-11FF-A725-27C6999C-A699-33CD614E75EC",          "rel": "delete",          "method": "DELETE"        }      ]    }  ],  "links": [    {      "href": "/v2/invoicing/invoices/INV2-S884-EJT6-73AU-QF4C/conditional-rules",      "rel": "self",      "method": "GET"    },    {      "href": "/v2/invoicing/invoices/INV2-S884-EJT6-73AU-QF4C",      "rel": "invoice",      "method": "GET"    }  ]}