Revert "Get python back a minor version 3.12->3.11"

This reverts commit 18b8b7269cfe0204218f7a23123255265da5cb6a.

Reason for revert: does not fix the issue

Original change's description:
> Get python back a minor version 3.12->3.11
>
> The previous bump to 3.12 generated a pip error [1] on gae-deploy builder. Looking up the failing grpcio wheel [2] we found no version for python 3.12 but we were able to find one for 3.11.
>
> [1] https://logs.chromium.org/logs/infradata-gae/buildbucket/cr-buildbucket/8730733229235940657/+/u/actuating_chrome-devtools-frontend-stg/deploying/stdout
> [2] https://chromium.googlesource.com/infra/infra/+/HEAD/infra/tools/dockerbuild/wheels.md#Wheel-List-grpcio
>
> Bug: 379873138
> Change-Id: Idaeec9ac48636b12057c8d77b9acda87353ebebd
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/chrome-devtools-frontend/+/6039767
> Commit-Queue: Liviu Rau <liviurau@chromium.org>
> Reviewed-by: Michael Achenbach <machenbach@chromium.org>

Bug: 379873138
Change-Id: I5c66e5b3cf246c37971ce1527f170d561d18a43e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/chrome-devtools-frontend/+/6039221
Commit-Queue: Liviu Rau <liviurau@chromium.org>
Reviewed-by: Liviu Rau <liviurau@chromium.org>
Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>