fix: instruct uv to install into system for CI (#5288)

Author: pipliggins

.github/workflows/benchmark_on_push.yml

@@ -40,7 +40,7 @@ jobs:
           enable-cache: true
 
       - name: Install python dependencies
-        run: uv pip install asv[virtualenv]
+        run: uv pip install --system asv
 
       - name: Fetch base branch
         run: |

.github/workflows/periodic_benchmarks.yml

@@ -48,7 +48,7 @@ jobs:
           enable-cache: true
 
       - name: Install python dependencies
-        run: uv pip install asv[virtualenv]
+        run: uv pip install --system asv
 
       - name: Run benchmarks
         run: |