Fix some text replacements

Author: MakisH

partitioned-heat-conduction/neumann-fenics/run.sh

@@ -4,9 +4,8 @@ set -e -u
 . ../../tools/log.sh
 exec > >(tee --append "$LOGFILE") 2>&1
 
-if [ $# -eq 0 ]
+if [ -z "${PRECICE_TUTORIALS_NO_VENV:-}" ]
 then
-    echo "Installing dependencies in a Python virtual environment"
     python3 -m venv --system-site-packages .venv
     . .venv/bin/activate
     pip install -r ../solver-fenics/requirements.txt

perpendicular-flap/fluid-su2/run.sh

@@ -4,9 +4,8 @@ set -e -u
 . ../../tools/log.sh
 exec > >(tee --append "$LOGFILE") 2>&1
 
-if [ $# -eq 0 ]
+if [ -z "${PRECICE_TUTORIALS_NO_VENV:-}" ]
 then
-    echo "Installing dependencies in a Python virtual environment"
     python3 -m venv --system-site-packages .venv
     . .venv/bin/activate
     pip install -r requirements.txt && pip freeze > pip-installed-packages.log

perpendicular-flap/solid-fenics/run.sh

@@ -4,9 +4,8 @@ set -e -u
 . ../../tools/log.sh
 exec > >(tee --append "$LOGFILE") 2>&1
 
-if [ $# -eq 0 ]
+if [ -z "${PRECICE_TUTORIALS_NO_VENV:-}" ]
 then
-    echo "Installing dependencies in a Python virtual environment"
     python3 -m venv --system-site-packages .venv
     . .venv/bin/activate
     pip install -r requirements.txt && pip freeze > pip-installed-packages.log