Experimental GitHub Multi-account support (#222131)

* Have select account picker include accounts that don't match requested scopes (this will run `createSession` for that chosen account)
* Implement multi-account GitHub support behind a setting

extensions/github-authentication/package.json

@@ -41,7 +41,7 @@
         "id": "github-enterprise"
       }
     ],
-    "configuration": {
+    "configuration": [{
       "title": "GitHub Enterprise Server Authentication Provider",
       "properties": {
         "github-enterprise.uri": {
@@ -49,7 +49,17 @@
           "description": "GitHub Enterprise Server URI"
         }
       }
+    },
+    {
+      "title": "GitHub Authentication",
+      "properties": {
+        "github.experimental.multipleAccounts": {
+          "type": "boolean",
+          "description": "Experimental support for multiple GitHub accounts"
+        }
+      }
     }
+  ]
   },
   "aiKey": "0c6ae279ed8443289764825290e4f9e2-1a736e7c-1324-4338-be46-fc2a58ae4d14-7255",
   "main": "./out/extension.js",