feat(graph/edu): Add externalID user property

devtools/deployments/multi-tenancy/initialize_users.go

@@ -31,11 +31,13 @@ var demoTenants = []tenantWithUsers{
 				DisplayName:              libregraph.PtrString("Dennis Ritchie"),
 				OnPremisesSamAccountName: libregraph.PtrString("dennis"),
 				Mail:                     libregraph.PtrString("dennis@example.org"),
+				ExternalId:               libregraph.PtrString("ExternalID1"),
 			},
 			{
 				DisplayName:              libregraph.PtrString("Grace Hopper"),
 				OnPremisesSamAccountName: libregraph.PtrString("grace"),
 				Mail:                     libregraph.PtrString("grace@example.org"),
+				ExternalId:               libregraph.PtrString("ExternalID2"),
 			},
 		},
 	},
@@ -49,11 +51,13 @@ var demoTenants = []tenantWithUsers{
 				DisplayName:              libregraph.PtrString("Albert Einstein"),
 				OnPremisesSamAccountName: libregraph.PtrString("einstein"),
 				Mail:                     libregraph.PtrString("einstein@example.org"),
+				ExternalId:               libregraph.PtrString("ExternalID3"),
 			},
 			{
 				DisplayName:              libregraph.PtrString("Marie Curie"),
 				OnPremisesSamAccountName: libregraph.PtrString("marie"),
 				Mail:                     libregraph.PtrString("marie@example.org"),
+				ExternalId:               libregraph.PtrString("ExternalID4"),
 			},
 		},
 	},