update json workflow condition and matrix dependency

Author: leighmcculloch

.github/workflows/newbuild.yml

@@ -147,10 +147,10 @@ jobs:
 
   build-dep:
     needs: [setup, prepare]
-    if: needs.prepare.outputs.deps-to-build
+    if: needs.prepare.outputs.deps-to-build != ''
     strategy:
       matrix:
-        dep: ${{ fromJSON(needs.prepare.outputs.deps-to-build || '[]') }}
+        dep: ${{ fromJSON(needs.prepare.outputs.deps-to-build) }}
       fail-fast: false
     name: build ${{ matrix.dep.name }} ${{ matrix.dep.repo }} ${{ matrix.dep.ref }} ${{ matrix.dep.arch }} ${{ matrix.dep.options && toJSON(matrix.dep.options) }}
     runs-on: ${{ matrix.dep.name == 'core' && (matrix.dep.arch == 'arm64' && 'ubuntu-jammy-16-cores-amd64' || 'ubuntu-latest-16-cores') || (matrix.dep.arch == 'arm64' && 'ubuntu-24.04-arm' || 'ubuntu-latest') }}