When creating a virtual environment, upgrade pip

Pip will be upgraded upon immediately creating the virtual environment.  If the pip upgrade fails, this should not cause the script to fail (treat as a warning).  After the environment is created, it will not attempt further updates to pip.

webui.sh

@@ -210,6 +210,7 @@ then
     if [[ ! -d "${venv_dir}" ]]
     then
         "${python_cmd}" -m venv "${venv_dir}"
+        "${venv_dir}"/bin/python -m pip install --upgrade pip
         first_launch=1
     fi
     # shellcheck source=/dev/null