Revert "ci: Upgrading pip version in macos environment"

This reverts commit 057750c.

It is not needed anymore in the GHA CI.
This change will make the code much simpler in the following commit.

Author: hebasto

ci/test/01_base_install.sh

@@ -32,7 +32,6 @@ fi
 
 if [ -n "$PIP_PACKAGES" ]; then
   if [ "$CI_OS_NAME" == "macos" ]; then
-    sudo -H pip3 install --upgrade pip
     # shellcheck disable=SC2086
     IN_GETOPT_BIN="$(brew --prefix gnu-getopt)/bin/getopt" ${CI_RETRY_EXE} pip3 install --user $PIP_PACKAGES
   else