build(deps): bump torchmetrics from 0.9.1 to 1.8.1 in /tests/e2e

Bumps [torchmetrics](https://github.com/Lightning-AI/torchmetrics) from 0.9.1 to 1.8.1.
- [Release notes](https://github.com/Lightning-AI/torchmetrics/releases)
- [Changelog](https://github.com/Lightning-AI/torchmetrics/blob/v1.8.1/CHANGELOG.md)
- [Commits](Lightning-AI/torchmetrics@v0.9.1...v1.8.1)

---
updated-dependencies:
- dependency-name: torchmetrics
  dependency-version: 1.8.1
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

tests/e2e/mnist_pip_requirements.txt

@@ -1,4 +1,4 @@
 pytorch_lightning==1.9.5
-torchmetrics==0.9.1
+torchmetrics==1.8.1
 torchvision==0.20.1
 minio