ci(workflows): ensure rpi-imager json generation runs always

Add `if: always()` to the `generate-rpi-imager-json` job to ensure the
JSON metadata is generated even if some of the preceding build jobs
fail or are skipped.

Author: florian-asche

.github/workflows/build-all.yml

@@ -73,4 +73,5 @@ jobs:
   # RPI IMAGER JSON
   generate-rpi-imager-json:
     needs: [build, build-2michat, build-respeaker_lite, build-2michat-lva, build-respeaker_lite-lva]
+    if: always()
     uses: ./.github/workflows/create-rpi-image-json.yml