[yang] bgp address family l2vpn advertise-all-vni (#21054)

Why I did it
Cannot configure unified bgp for vxlan evpn without specifying advertise-all-vpn. The setting appears to have been introduced as part of PR #5142, can be seen it is already honored as an option here:

sonic-buildimage/src/sonic-frr-mgmt-framework/templates/bgpd/bgpd.conf.db.addr_family.evpn.j2

Lines 1 to 3 in 8e0f1c6

 {% if 'advertise-all-vni' in af_val and af_val['advertise-all-vni'] == 'true' %} 
   advertise-all-vni 
 {% endif %} 
Work item tracking
How I did it
Added basic yang rule

How to verify it
Configure

"BGP_GLOBALS_AF": {
        "default|l2vpn_evpn": {
            "advertise-all-vni": "true"
        }
    }
and run config replace.

Tested branch (Please provide the tested image version)
master as of 20241205

Description for the changelog
[yang] bgp address family l2vpn advertise-all-vni

Author: bradh352

src/sonic-yang-models/tests/files/sample_config_db.json

@@ -1771,6 +1771,9 @@
             "default|ipv6_unicast": {
                 "max_ebgp_paths": "2",
                 "max_ibgp_paths": "2"
+            },
+            "default|l2vpn_evpn": {
+                "advertise-all-vni": "true"
             }
         },
         "BGP_GLOBALS_AF_AGGREGATE_ADDR": {

src/sonic-yang-models/tests/yang_model_tests/tests/bgp.json

@@ -2,6 +2,16 @@
     "BGP_GLOBAL_VALID": {
         "desc": "Configure BGP global table."
     },
+    "BGP_GLOBALS_AF_ADVERTISE_ALL_VNI_TRUE": {
+        "desc": "BGP Address Family l2vpn_evpn with advertise-all-vni set to true"
+    },
+    "BGP_GLOBALS_AF_ADVERTISE_ALL_VNI_FALSE": {
+        "desc": "BGP Address Family l2vpn_evpn with advertise-all-vni set to false"
+    },
+    "BGP_GLOBALS_AF_ADVERTISE_ALL_VNI_INVALID": {
+        "desc": "BGP Address Family l2vpn_evpn with advertise-all-vni set to an invalid value",
+        "eStr": "Invalid value \"invalid value\" in \"advertise-all-vni\" element."
+    },
     "BGP_NEIGHBOR_ALL_VALID": {
         "desc": "Configure BGP neighbor table."
     },

src/sonic-yang-models/tests/yang_model_tests/tests_config/bgp.json

@@ -81,7 +81,69 @@
             }
         }
     },
-
+    "BGP_GLOBALS_AF_ADVERTISE_ALL_VNI_TRUE": {
+        "sonic-bgp-global:sonic-bgp-global": {
+            "sonic-bgp-global:BGP_GLOBALS": {
+                "BGP_GLOBALS_LIST": [
+                {
+                    "vrf_name":"default",
+                    "local_asn": 65001
+                }
+                ]
+            },
+            "sonic-bgp-global:BGP_GLOBALS_AF": {
+                "BGP_GLOBALS_AF_LIST": [
+                {
+                    "vrf_name": "default",
+                    "afi_safi": "l2vpn_evpn",
+                    "advertise-all-vni": "true"
+                }
+                ]
+            }
+        }
+    },
+    "BGP_GLOBALS_AF_ADVERTISE_ALL_VNI_FALSE": {
+        "sonic-bgp-global:sonic-bgp-global": {
+            "sonic-bgp-global:BGP_GLOBALS": {
+                "BGP_GLOBALS_LIST": [
+                {
+                    "vrf_name":"default",
+                    "local_asn": 65001
+                }
+                ]
+            },
+            "sonic-bgp-global:BGP_GLOBALS_AF": {
+                "BGP_GLOBALS_AF_LIST": [
+                {
+                    "vrf_name": "default",
+                    "afi_safi": "l2vpn_evpn",
+                    "advertise-all-vni": "false"
+                }
+                ]
+            }
+        }
+    },
+    "BGP_GLOBALS_AF_ADVERTISE_ALL_VNI_INVALID": {
+        "sonic-bgp-global:sonic-bgp-global": {
+            "sonic-bgp-global:BGP_GLOBALS": {
+                "BGP_GLOBALS_LIST": [
+                {
+                    "vrf_name":"default",
+                    "local_asn": 65001
+                }
+                ]
+            },
+            "sonic-bgp-global:BGP_GLOBALS_AF": {
+                "BGP_GLOBALS_AF_LIST": [
+                {
+                    "vrf_name": "default",
+                    "afi_safi": "l2vpn_evpn",
+                    "advertise-all-vni": "invalid value"
+                }
+                ]
+            }
+        }
+    },
     "BGP_NEIGHBOR_ALL_VALID": {
         "sonic-port:sonic-port": {
             "sonic-port:PORT": {

src/sonic-yang-models/yang-models/sonic-bgp-global.yang

@@ -445,6 +445,11 @@ module sonic-bgp-global {
                     }
                     description "Maximum duration to suppress a stable route";
                 }
+
+                leaf advertise-all-vni {
+                    type boolean;
+                    description "L2VPN advertise all VNIs";
+                }
             }
         }