Modify the core sampler install script

ci/pex-build.template.yml

@@ -2,7 +2,7 @@
 .build-pexes:
     image: python:3.10
     script:
-        - pip install build twine
+        - pip install build twine pytest
         - python -m build ${PEX_PATH}
         - pip install ${PEX_PATH}
         - NAME=$(awk -F' = ' '/^\[tool.poetry\]/ { project = 1; next } /^\[.*\]/ { project = 0 } project && $1 == "name" { gsub(/"/, "", $2); print $2 }' ${PEX_PATH}/pyproject.toml)