Do not reflect label names in request metrics' "route" label

[dannykopping]

Which issue(s) this PR fixes:
Fixes #11549

Checklist

• Reviewed the CONTRIBUTING.md guide (required)
• Documentation added
• Tests updated
• CHANGELOG.md updated
  • If the change is worth mentioning in the release notes, add add-to-release-notes label
• Changes that require user attention or interaction to upgrade are documented in docs/sources/setup/upgrade/_index.md
• For Helm chart changes bump the Helm chart version in production/helm/loki/Chart.yaml and update production/helm/loki/CHANGELOG.md and production/helm/loki/README.md. Example PR
• If the change is deprecating or removing a configuration option, update the deprecated-config.yaml and deleted-config.yaml files respectively in the tools/deprecated-config-checker directory. Example PR

[github-actions]

Trivy scan found the following vulnerabilities:

• HIGH, Target: docker.io/grafana/loki:main-afe146c (alpine 3.18.4), Type: alpine openssl: Incorrect cipher key and IV length processing in libcrypto3 v3.1.3-r0. Fixed in v3.1.4-r0
• HIGH, Target: docker.io/grafana/loki:main-afe146c (alpine 3.18.4), Type: alpine openssl: Incorrect cipher key and IV length processing in libssl3 v3.1.3-r0. Fixed in v3.1.4-r0
  \nTo see more details on these vulnerabilities, and how/where to fix them, please run docker build -t grafana/loki:main-afe146c -f cmd/loki/Dockerfile .
  trivy i grafana/loki:main-afe146c on your branch. If these were not introduced by your PR, please considering fixing them in via a subsequent PR. Thanks!

[grafanabot]

Hello @dannykopping!
Backport pull requests need to be either:

• Pull requests which address bugs,
• Urgent fixes which need product approval, in order to get merged,
• Docs changes.

Please, if the current pull request addresses a bug fix, label it with the type/bug label.
If it already has the product approval, please add the product-approved label. For docs changes, please add the type/docs label.
If the pull request modifies CI behaviour, please add the type/ci label.
If none of the above applies, please consider removing the backport label and target the next major/minor release.
Thanks!

[grafanabot]

Hello @dannykopping!
Backport pull requests need to be either:

• Pull requests which address bugs,
• Urgent fixes which need product approval, in order to get merged,
• Docs changes.

Please, if the current pull request addresses a bug fix, label it with the type/bug label.
If it already has the product approval, please add the product-approved label. For docs changes, please add the type/docs label.
If the pull request modifies CI behaviour, please add the type/ci label.
If none of the above applies, please consider removing the backport label and target the next major/minor release.
Thanks!

[grafanabot]

The backport to release-2.8.x failed:

The process '/usr/bin/git' failed with exit code 1

To backport manually, run these commands in your terminal:

# Fetch latest updates from GitHub
git fetch
# Create a new branch
git switch --create backport-11551-to-release-2.8.x origin/release-2.8.x
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick -x 18ea38883f62bb8b28150a1f42ccd2d74fb03389

When the conflicts are resolved, stage and commit the changes:

git add . && git cherry-pick --continue

If you have the GitHub CLI installed:

# Push the branch to GitHub:
git push --set-upstream origin backport-11551-to-release-2.8.x
# Create the PR body template
PR_BODY=$(gh pr view 11551 --json body --template 'Backport 18ea38883f62bb8b28150a1f42ccd2d74fb03389 from #11551{{ "\n\n---\n\n" }}{{ index . "body" }}')
# Create the PR on GitHub
echo "${PR_BODY}" | gh pr create --title "[release-2.8.x] Do not reflect label names in request metrics' \"route\" label" --body-file - --label "size/XS" --label "type/bug" --label "backport" --base release-2.8.x --milestone release-2.8.x --web

Or, if you don't have the GitHub CLI installed (we recommend you install it!):

# Push the branch to GitHub:
git push --set-upstream origin backport-11551-to-release-2.8.x

# Create a pull request where the `base` branch is `release-2.8.x` and the `compare`/`head` branch is `backport-11551-to-release-2.8.x`.

# Remove the local backport branch
git switch main
git branch -D backport-11551-to-release-2.8.x