debugger: Improve debugger panel empty state (#32889)

Before:

![CleanShot 2025-06-17 at 13 48
58@2x](https://github.com/user-attachments/assets/16ecebfa-871e-4a2d-b6a3-2178de70aaef)

After:

![CleanShot 2025-06-17 at 13 49
24@2x](https://github.com/user-attachments/assets/2d8a0444-6088-45f1-a880-0bdd0aef968e)


Release Notes:

- N/A (Beta: Improved the debugger panel when there are no currently
active sessions)

assets/icons/blocks.svg

@@ -1 +1 @@
-<svg xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" class="lucide lucide-blocks"><rect width="7" height="7" x="14" y="3" rx="1"/><path d="M10 21V8a1 1 0 0 0-1-1H4a1 1 0 0 0-1 1v12a1 1 0 0 0 1 1h12a1 1 0 0 0 1-1v-5a1 1 0 0 0-1-1H3"/></svg>
+<svg xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" class="lucide lucide-blocks-icon lucide-blocks"><rect width="7" height="7" x="14" y="3" rx="1"/><path d="M10 21V8a1 1 0 0 0-1-1H4a1 1 0 0 0-1 1v12a1 1 0 0 0 1 1h12a1 1 0 0 0 1-1v-5a1 1 0 0 0-1-1H3"/></svg>