Make test-fast CI matrix run all jobs even when one fails

To see if this can sometimes reproduce #2006 even outside macOS.

The `fail-fast: false` added here can be removed after testing.

Author: EliahKagan

.github/workflows/ci.yml

@@ -164,6 +164,7 @@ jobs:
           - macos-latest
           - ubuntu-latest
           - ubuntu-24.04-arm
+      fail-fast: false
 
     runs-on: ${{ matrix.os }}