[DataFactory] GitHub bring your own app swagger update for ADF/Synapse Dataplane only (Azure#14689)

* GitHub bring your own app swagger changes for ADF/Synapse

* fix different githubclientsecret description lint error

* Separate dataplane changes to support GitHub BYOA in ADF/Synapse

* remove unnecessary discriminator

Author: jmcallister-msft

specification/datafactory/resource-manager/Microsoft.DataFactory/stable/2018-06-01/datafactory.json

@@ -5015,6 +5015,20 @@
         }
       }
     },
+    "GitHubClientSecret": {
+      "description": "Client secret information for factory's bring your own app repository configuration.",
+      "type": "object",
+      "properties": {
+        "byoaSecretAkvUrl": {
+          "description": "Bring your own app client secret AKV URL.",
+          "type": "string"
+        },
+        "byoaSecretName": {
+          "description": "Bring your own app client secret name in AKV.",
+          "type": "string"
+        }
+      }
+    },
     "FactoryRepoUpdate": {
       "description": "Factory's git repo information.",
       "properties": {
@@ -5039,6 +5053,10 @@
           "description": "GitHub application client ID.",
           "type": "string"
         },
+        "gitHubClientSecret": {
+          "$ref": "#/definitions/GitHubClientSecret",
+          "description": "GitHub bring your own app client secret information."
+        },
         "gitHubAccessTokenBaseUrl": {
           "description": "GitHub access token base URL.",
           "type": "string"

specification/synapse/data-plane/Microsoft.Synapse/preview/2019-06-01-preview/gitintegration.json

@@ -71,13 +71,31 @@
     }
   },
   "definitions": {
+    "GitHubClientSecret": {
+      "description": "Client secret information for factory's bring your own app repository configuration",
+      "type": "object",
+      "properties": {
+        "byoaSecretAkvUrl": {
+          "description": "Bring your own app client secret AKV URL",
+          "type": "string"
+        },
+        "byoaSecretName": {
+          "description": "Bring your own app client secret name in AKV",
+          "type": "string"
+        }
+      }
+    },
     "GitHubAccessTokenRequest": {
       "type": "object",
       "properties": {
         "gitHubClientId": {
           "description": "The GitHub Client Id.",
           "type": "string"
         },
+        "gitHubClientSecret": {
+          "$ref": "#/definitions/GitHubClientSecret",
+          "description": "GitHub bring your own app client secret information."
+        },
         "gitHubAccessCode": {
           "description": "The GitHub Access code.",
           "type": "string"