Fix clearing the token

The previous version would have interpreted an empty token as
an abort of the dialog and would have not properly cleared the token.
This is now fixed by checking for `undefined` for a an abort and
by setting the token to `undefined` in order to clear it.

Author: Matthias247

editors/code/src/main.ts

@@ -393,8 +393,13 @@ async function queryForGithubToken(state: PersistentState): Promise<void> {
     };
 
     const newToken = await vscode.window.showInputBox(githubTokenOptions);
-    if (newToken) {
-        log.info("Storing new github token");
-        await state.updateGithubToken(newToken);
+    if (newToken !== undefined) {
+        if (newToken === "") {
+            log.info("Clearing github token");
+            await state.updateGithubToken(undefined);
+        } else {
+            log.info("Storing new github token");
+            await state.updateGithubToken(newToken);
+        }
     }
 }