ci: use blobless source-smoke checkout

Author: kkraus14

.github/workflows/ci-pixi-source-test.yml

@@ -77,6 +77,7 @@ jobs:
           # package version; a shallow checkout yields 0.1.dev1, which trips
           # cuda.core's "cuda.bindings 12.x or 13.x must be installed" guard.
           fetch-depth: 0
+          filter: blob:none
 
       - name: Setup pixi
         # Pinned to a commit SHA; install logic lives in the action and is
@@ -212,6 +213,7 @@ jobs:
           # package version; a shallow checkout yields 0.1.dev1, which trips
           # cuda.core's "cuda.bindings 12.x or 13.x must be installed" guard.
           fetch-depth: 0
+          filter: blob:none
 
       - name: Setup proxy cache
         uses: nv-gha-runners/setup-proxy-cache@main