Make sympy installation non-fatal on macOS and use --break-system-packages

- Add --break-system-packages flag along with --user to comply with PEP 668
- Make sympy installation non-fatal using set +e/set -e
- Since sympy is optional (tests work without it), continue even if installation fails
- This fixes the externally-managed-environment error on macOS CI runners

Author: ahmed-irfan

.github/actions/install-dependencies/action.yml

@@ -24,12 +24,17 @@ runs:
         ## gmp and python are already installed in the latest macOS
         # brew install gmp
         # brew install python
+        ## Try to install sympy, but don't fail if it doesn't work (it's optional)
+        ## sympy is optional - tests will work without it
+        ## Use --break-system-packages with --user as recommended by PEP 668
+        set +e  # Don't exit on error
         if command -v pip3 &> /dev/null; then
-          pip3 install --user sympy
+          pip3 install --user --break-system-packages sympy || echo "Warning: Failed to install sympy with pip3, continuing anyway"
         elif python3 -m pip --version &> /dev/null; then
-          python3 -m pip install --user sympy
+          python3 -m pip install --user --break-system-packages sympy || echo "Warning: Failed to install sympy with python3 -m pip, continuing anyway"
         else
-          python3 -m ensurepip --upgrade || python3 -m ensurepip
-          python3 -m pip install --user sympy
+          python3 -m ensurepip --upgrade || python3 -m ensurepip || true
+          python3 -m pip install --user --break-system-packages sympy || echo "Warning: Failed to install sympy, continuing anyway"
         fi
+        set -e  # Re-enable exit on error
         echo "Install Mac dependencies [DONE]"