ci: remove check of gettext files with msgcheck

Use only poexam to check gettext files.

.github/workflows/ci.yml

@@ -133,7 +133,7 @@ jobs:
       run: |
         sudo apt-get update -qq
         sudo apt-get --yes --no-install-recommends install ${{ env.CHECK_DEPS_UBUNTU }}
-        pipx install msgcheck ruff
+        pipx install ruff
 
     - name: Cache poexam
       id: cache-poexam
@@ -146,10 +146,7 @@ jobs:
       if: steps.cache-poexam.outputs.cache-hit != 'true'
       run: cargo install --version "$POEXAM_VERSION" poexam
 
-    - name: Check gettext files (msgcheck)
-      run: msgcheck po/*.po
-
-    - name: Check gettext files (poexam)
+    - name: Check gettext files
       run: poexam check --file-stats --rule-stats
 
     - name: Check shell and Python scripts