chore(ci): update link-checker to v1.2.5 (#6602)

Update link-checker to v1.2.5 which adds --root-dir support for lychee v0.22.0+.

This fixes CI failures caused by lychee v0.22.0 (released Dec 5, 2025)
requiring --root-dir to resolve root-relative links in local files.
The link-checker now automatically sets --root-dir to the Hugo public/
directory when checking local HTML files.

Fixes failures for PRs touching /telegraf/v1 and /influxdb3/explorer paths.

Author: jstirnaman

.github/workflows/pr-link-check.yml

@@ -95,7 +95,7 @@ jobs:
           curl -L -H "Accept: application/vnd.github+json" \
             -H "Authorization: Bearer ${{ secrets.GITHUB_TOKEN }}" \
             -o link-checker-info.json \
-            "https://api.github.com/repos/influxdata/docs-v2/releases/tags/link-checker-v1.2.4"
+            "https://api.github.com/repos/influxdata/docs-v2/releases/tags/link-checker-v1.2.5"
           
           # Extract download URL for linux binary
           DOWNLOAD_URL=$(jq -r '.assets[] | select(.name | test("link-checker.*linux")) | .url' link-checker-info.json)