Restore immediate deletion of transient .quarto_ipynb after execution

When keep-ipynb is false (the default), cleanupNotebook() now calls
safeRemoveSync() to delete the intermediate .quarto_ipynb file immediately
after execution, restoring the original behavior from 2021 that was
inadvertently dropped when keep-ipynb support was added in PR #12793.

Author: cderv

src/execute/jupyter/jupyter.ts

@@ -7,7 +7,7 @@
 import { basename, dirname, join, relative } from "../../deno_ral/path.ts";
 import { satisfies } from "semver/mod.ts";
 
-import { existsSync } from "../../deno_ral/fs.ts";
+import { existsSync, safeRemoveSync } from "../../deno_ral/fs.ts";
 
 import { error, info } from "../../deno_ral/log.ts";
 
@@ -870,6 +870,8 @@ function cleanupNotebook(
     if (cached.target && cached.target.data) {
       (cached.target.data as JupyterTargetData).transient = false;
     }
+  } else if (data.transient) {
+    safeRemoveSync(target.input);
   }
 }