Artifact name per platform, overwrite previous artifact

This implies that our nightly artifacts get overwritten per platform. To avoid this, give unique names and remove `overwrite: true`

For compatibility with actions@v4

Author: gemenerik

.github/workflows/nightly-experiment.yml

@@ -35,5 +35,6 @@ jobs:
     - name: Upload Build Artifact
       uses: actions/upload-artifact@v4
       with:
-        name: nightly-experiment
+        name: ${{ matrix.platform }}-nightly
         path: firmware-${{ matrix.platform }}-nightly-experiment.zip
+        overwrite: true

.github/workflows/nightly.yml

@@ -35,5 +35,6 @@ jobs:
     - name: Upload Build Artifact
       uses: actions/upload-artifact@v4
       with:
-        name: nightly
+        name: ${{ matrix.platform }}-nightly
         path: firmware-${{ matrix.platform }}-nightly.zip
+        overwrite: true