Set pipefail in demo-native action (#1950)

Set `pipefail` in shell.  Otherwise the pipe will exit w/ success since sed exits w/ 0.

Co-authored-by: tbro <tbro@users.noreply.github.com>

.github/workflows/test-demo-native.yml

@@ -49,5 +49,6 @@ jobs:
       - name: Test Demo
         run: |
           export PATH="$PWD/target/release:$PATH"
+          set -o pipefail
           scripts/demo-native --tui=false &
           timeout -v 600 scripts/smoke-test-demo | sed -e 's/^/smoke-test: /;'