Bump python from 3.12-slim to 3.14-slim in /tests/e2e

Bumps python from 3.12-slim to 3.14-slim.

---
updated-dependencies:
- dependency-name: python
  dependency-version: 3.14-slim
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

tests/e2e/Dockerfile

@@ -1,4 +1,4 @@
-FROM python:3.12-slim
+FROM python:3.14-slim
 
 RUN apt-get update \
  && apt-get install -y --no-install-recommends util-linux e2fsprogs btrfs-progs \