ci: enable dialyzer checks (4.3)

.github/workflows/build_slim_packages.yaml

@@ -49,12 +49,7 @@ jobs:
     - name: make xref
       run: make xref
     - name: make dialyzer
-      run: |
-        # TODO: once dialyzer warnings are fixed in 4.4+, we may
-        # enforce this.
-        if [[ "$(./pkg-vsn.sh)" =~ 4.3.* ]]; then
-          make dialyzer
-        fi
+      run: make dialyzer
     - name: build zip packages
       run: make ${EMQX_NAME}-zip
     - name: build deb/rpm packages