Deno-bundled artifacts fail to register with Firebase Functions

### [REQUIRED] Environment info

**firebase-tools:** 15.0.0

**Platform:** Linux

### [REQUIRED] Test case

A minimal reproduction repository is available here: https://github.com/snorreks/deno-firebase-functions-bundle-bug

The repository contains a simple HTTP function and scripts to demonstrate the bundling issue.

```typescript
// src/index.ts
import { onRequest } from "firebase-functions/v2/https";
import { initializeApp } from "firebase-admin/app";

initializeApp();

export const hello = onRequest((req, res) => {
res.send("Hello from Firebase!");
});
```

### [REQUIRED] Steps to reproduce

1. Clone the reproduction repository: `git clone https://github.com/snorreks/deno-firebase-functions-bundle-bug.git`
2. `cd deno-firebase-functions-bundle-bug`
3. Run the Deno build script to generate the problematic bundle: `deno run -A --unstable-bundle build.ts`
4. Navigate to the directory containing the Deno-generated bundle: `cd dist/deno-bundle`
5. Attempt to deploy the function: `firebase deploy --only functions`

### [REQUIRED] Expected behavior

The `firebase deploy` command should correctly identify the `hello` function within the bundled `index.js` file and proceed with the deployment.

### [REQUIRED] Actual behavior

The `firebase deploy` command fails immediately with the following error, indicating it cannot parse the bundled artifact to find the Functions SDK.

```
Error: Failed to find location of Firebase Functions SDK. Please file a bug on Github (https://github.com/firebase/firebase-tools/).
```

This issue occurs specifically when the code is bundled using Deno's native bundling capabilities (`Deno.bundle`) or tools that use its resolution logic (like `@luca/esbuild-deno-loader`). Bundling the exact same source code with standard Node.js-based `esbuild` results in a successful deployment, which points to an incompatibility between how the Firebase CLI discovers functions and how Deno generates its ESM output for Node.js targets.