build(ci): reclaim disk space on emulator runner

it is relatively easy to do an rm-rf directly but there are maintained
workflow actions that remove everything for you

This is the most-maintained fork of the most popular one I've used before

It defaults to true, and each item you remove takes time. I think dotnet
is the biggest one and should be sufficient so only remove it and that
should be sufficient

.github/workflows/tests_emulator.yml

@@ -40,6 +40,17 @@ jobs:
         # This is useful for benchmarking, do 0, 1, 2, etc (up to 256 max job-per-matrix limit) for averages
         iteration: [0]
     steps:
+      - name: Free Disk Space (Ubuntu)
+        uses: insightsengineering/disk-space-reclaimer@v1
+        with:
+          tools-cache: false
+          android: false
+          dotnet: true
+          haskell: false
+          large-packages: false
+          swap-storage: false
+          docker-images: false
+
       - name: Test Credential Prep
         run: |
           echo "KSTOREPWD=$STOREPASS" >> $GITHUB_ENV