fix(reusable-zizmor): skip empty ZIZMOR_CONFIG variable

Author: zerok

.github/workflows/reusable-zizmor.yml

@@ -380,12 +380,14 @@ jobs:
           ZIZMOR_CACHE_DIR: ${{ runner.temp }}/.cache/zizmor
         shell: sh
         run: >-
+          if [ -z "${ZIZMOR_CONFIG}" ]; then
+            unset ZIZMOR_CONFIG
+          fi
           uvx zizmor@"${ZIZMOR_VERSION}"
           --format sarif
           --min-severity "${MIN_SEVERITY}"
           --min-confidence "${MIN_CONFIDENCE}"
           --cache-dir "${ZIZMOR_CACHE_DIR}"
-          ${ZIZMOR_CONFIG:+--config "${ZIZMOR_CONFIG}"}
           ${RUNNER_DEBUG:+"--verbose"}
           ${ZIZMOR_EXTRA_ARGS:+${ZIZMOR_EXTRA_ARGS}}
           .
@@ -419,13 +421,15 @@ jobs:
           # don't fail the build if zizmor fails - we want to capture the output
           # and the exit code
           set +e
+          if [ -z "${ZIZMOR_CONFIG}" ]; then
+            unset ZIZMOR_CONFIG
+          fi
           uvx zizmor@"${ZIZMOR_VERSION}" \
             --format plain \
             --min-severity "${MIN_SEVERITY}" \
             --min-confidence "${MIN_CONFIDENCE}" \
             --cache-dir "${ZIZMOR_CACHE_DIR}" \
             ${RUNNER_DEBUG:+"--verbose"} \
-            ${ZIZMOR_CONFIG:+--config "${ZIZMOR_CONFIG}"} \
             ${ZIZMOR_EXTRA_ARGS:+${ZIZMOR_EXTRA_ARGS}} \
             . \
             | tee -a "${GITHUB_OUTPUT}"