perf(github-actions): compress preview artifacts before uploading

The `actions/upload` infrastructure will upload all files individually,
but we can compress it directly beforehand and just upload a single
smaller file.

This means that we need to unzip -> and then untar as GitHub
always zips up the artifacts regardless when they are uploaded.

This is expected and recommended as per:
https://github.com/actions/upload-artifact

github-actions/deploy-previews/pack-and-upload-artifact/action.yml

@@ -52,7 +52,16 @@ runs:
           '${{inputs.pull-number}}' \
           '${{inputs.artifact-build-revision}}'
 
+    - name: Creating compressed tarball of artifact
+      id: pack
+      shell: bash
+      run: |
+        pkg="$RUNNER_TEMP/deploy-artifact.tar.gz"
+
+        tar -czvf "$pkg" -C '${{steps.copy.outputs.deploy-dir}}' .
+        echo "artifact-path=$pkg" >> $GITHUB_OUTPUT
+
     - uses: actions/upload-artifact@83fd05a356d7e2593de66fc9913b3002723633cb # renovate: tag=v3
       with:
         name: '${{inputs.workflow-artifact-name}}'
-        path: '${{steps.copy.outputs.deploy-dir}}'
+        path: '${{steps.pack.outputs.artifact-path}}'

github-actions/deploy-previews/upload-artifacts-to-firebase/action.yml

@@ -61,8 +61,13 @@ runs:
     - name: Extracting workflow artifact into Firebase public directory.
       shell: bash
       run: |
+        extractDir="$RUNNER_TEMP/artifact-unpack"
+
         mkdir -p '${{inputs.firebase-public-dir}}'
-        unzip unsafe-artifact.zip -d '${{inputs.firebase-public-dir}}'
+        mkdir -p "$extractDir"
+
+        unzip unsafe-artifact.zip -d "$extractDir"
+        tar -xvzf "$extractDir/deploy-artifact.tar.gz" -C '${{inputs.firebase-public-dir}}'
 
     - name: Extracting artifact metadata
       id: artifact-info