Fix to activate venv environment while testing pypi dist

Author: safaricd

.github/workflows/release.yml

@@ -89,7 +89,7 @@ jobs:
       - name: Wait for TestPyPI propagation
         run: |
           echo "⏳ Waiting for package to be available on TestPyPI..."
-          sleep 10
+          sleep 30
 
       - name: Test installation from TestPyPI
         run: |
@@ -106,10 +106,8 @@ jobs:
           source .venv/bin/activate
           
           # Install from TestPyPI using uv
-          # Use --index-url for TestPyPI and --extra-index-url for dependencies from PyPI
           uv pip install \
             --index-url https://test.pypi.org/simple/ \
-            --extra-index-url https://pypi.org/simple/ \
             tabpfn-common-utils==${VERSION}
           
           # Verify installation and version