Remove duplicate docsgen CI check

`docsgen` make target is already a dependency of `gen` which has a CI
check. We do not need to check `docsgen` separately for conformance.

Fixes #12498

.github/workflows/check.yml

@@ -20,19 +20,6 @@ permissions:
   contents: read
 
 jobs:
-  check-docsgen:
-    name: Check (docs-check)
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@v4
-        with:
-          submodules: 'recursive'
-      - uses: ./.github/actions/install-system-dependencies
-      - uses: ./.github/actions/install-go
-      - run: go install golang.org/x/tools/cmd/goimports
-      - run: make deps
-      - run: make docsgen
-      - run: git diff --exit-code
   check-gen:
     name: Check (gen-check)
     runs-on: ubuntu-latest