Using python -m venv for Venv Creation for UV Lock Scenarios (#2829)

* using python -m venv for venv creation for all scenarios

* changing approach

* Added log message for indication

---------

Co-authored-by: Pratham Bande <prathambande@microsoft.com>

Author: prathambande

src/BuildScriptGenerator/Python/PythonBashBuildSnippet.sh.tpl

@@ -168,7 +168,7 @@ install_python_packages_impl() {
     echo "Python Virtual Environment: $VIRTUALENVIRONMENTNAME"
 
     if [ -e "pyproject.toml" ] && [ -e "uv.lock" ] && [ ! -e "$REQUIREMENTS_TXT_FILE" ]; then
-        echo "Detected uv.lock (and no $REQUIREMENTS_TXT_FILE); creating virtual environment with uv..."
+        echo "Detected uv.lock (and no $REQUIREMENTS_TXT_FILE)"
         echo "Installing uv..."
         START_TIME=$SECONDS
         InstallUv="python -m pip install uv"
@@ -177,15 +177,23 @@ install_python_packages_impl() {
         ELAPSED_TIME=$(($SECONDS - $START_TIME))
         echo "Installing uv done in $ELAPSED_TIME sec(s)."
         CreateVenvCommand="uv venv --link-mode=copy --system-site-packages $VIRTUALENVIRONMENTNAME"
+        VIRTUALENVIRONMENTOPTIONS="$VIRTUALENVIRONMENTOPTIONS --system-site-packages"
     else
         if [ -e "$REQUIREMENTS_TXT_FILE" ]; then
             VIRTUALENVIRONMENTOPTIONS="$VIRTUALENVIRONMENTOPTIONS --system-site-packages"
         fi
         CreateVenvCommand="$python -m $VIRTUALENVIRONMENTMODULE $VIRTUALENVIRONMENTNAME $VIRTUALENVIRONMENTOPTIONS"
     fi
 
-    echo Creating virtual environment...
+    if [ "$CreateVenvWithPythonVenv" = "true" ]; then
+        if [[ "$CreateVenvCommand" == *"uv venv"* ]]; then
+            echo "Using Python's built-in venv for virtual environment creation"
+        fi
+        CreateVenvCommand="$python -m $VIRTUALENVIRONMENTMODULE $VIRTUALENVIRONMENTNAME $VIRTUALENVIRONMENTOPTIONS"
+    fi
 
+    echo Creating virtual environment...
+
     echo "BuildCommands=$CreateVenvCommand" >> "$COMMAND_MANIFEST_FILE"
 
     # Execute the resolved CreateVenvCommand