[integration] fix: modify echo in function installDIRACX() where error occurs

[martynia]

Function installDIRACX() in utilities.sh had a malformed echo statement which referred to undefined variables.

*Tests
FIX: print a correct package name and a source directory.

The error would normally not pop up in CI since the GitHub workflow created necessary wheels:

pip install build
for pkg_dir in $PWD/diracx-* .; do
echo "Building $pkg_dir"
python -m build --outdir "${GITHUB_WORKSPACE}/dist" $pkg_dir

And when trying to run tests locally I naively issued a command:

./integration_tests.py prepare-environment "TEST_DIRACX=Yes" --diracx-dist-dir <my_diracX_source_tree>"

without building the wheels first.

[aldbr]

Basic tests are failing because of a trailing space in release-notes. #7868 should fix it.