Added parameter required_frontend_version in the /system_stats API response (#8875)

* Added the parameter required_frontend_version in the /system_stats  api response

* Update server.py

* Created a function get_required_frontend_version and wrote tests for it

* Refactored the function to return currently installed frontend pacakage version

* Moved required_frontend to a new function and imported that in server.py

* Corrected test cases using mocking techniques

* Corrected files to comply with ruff formatting

tests-unit/app_test/frontend_manager_test.py

@@ -1,7 +1,7 @@
 import argparse
 import pytest
 from requests.exceptions import HTTPError
-from unittest.mock import patch
+from unittest.mock import patch, mock_open
 
 from app.frontend_management import (
     FrontendManager,
@@ -172,3 +172,36 @@ def test_init_frontend_fallback_on_error():
     # Assert
     assert frontend_path == "/default/path"
     mock_check.assert_called_once()
+
+
+def test_get_frontend_version():
+    # Arrange
+    expected_version = "1.25.0"
+    mock_requirements_content = """torch
+torchsde
+comfyui-frontend-package==1.25.0
+other-package==1.0.0
+numpy"""
+
+    # Act
+    with patch("builtins.open", mock_open(read_data=mock_requirements_content)):
+        version = FrontendManager.get_required_frontend_version()
+
+    # Assert
+    assert version == expected_version
+
+
+def test_get_frontend_version_invalid_semver():
+    # Arrange
+    mock_requirements_content = """torch
+torchsde
+comfyui-frontend-package==1.29.3.75
+other-package==1.0.0
+numpy"""
+
+    # Act
+    with patch("builtins.open", mock_open(read_data=mock_requirements_content)):
+        version = FrontendManager.get_required_frontend_version()
+
+    # Assert
+    assert version is None