Add another clean-output since CI seems to run out of space on builds (…

…project-chip#28226)

.github/workflows/build.yaml

@@ -248,6 +248,8 @@ jobs:
                        --file-exclude-regex '/(repo|zzz_generated|lwip/standalone)/' \
                        check \
                     "
+            - name: Clean output
+              run: rm -rf ./out
             - name: Build using build_examples.py
               timeout-minutes: 60
               run: |