bugfix: parse password on db connection string when it has @ on It (#3173)

* ✨ (test_connection_string.py): add unit test for the transform_connection_string function to ensure correct transformation of connection strings

* 📝 (pgvector.py): add support for parsing and transforming connection string in PGVectorStoreComponent to improve security and maintainability
📝 (connection_string_parser.py): create utility function to transform connection string by encoding password to improve security
📝 (test_connection_string_parser.py): add unit tests for transform_connection_string function to ensure correct transformation of connection string

* test: fix import

---------

Co-authored-by: italojohnny <italojohnnydosanjos@gmail.com>

src/backend/tests/unit/utils/test_connection_string_parser.py

@@ -0,0 +1,25 @@
+import pytest
+from langflow.utils.connection_string_parser import transform_connection_string
+
+
+@pytest.fixture
+def client():
+    pass
+
+
+@pytest.mark.parametrize(
+    "connection_string, expected",
+    [
+        ("protocol:user:password@host", "protocol:user:password@host"),
+        ("protocol:user@host", "protocol:user@host"),
+        ("protocol:user:pass@word@host", "protocol:user:pass%40word@host"),
+        ("protocol:user:pa:ss:word@host", "protocol:user:pa:ss:word@host"),
+        ("user:password@host", "user:password@host"),
+        ("protocol::password@host", "protocol::password@host"),
+        ("protocol:user:password@", "protocol:user:password@"),
+        ("protocol:user:pa@ss@word@host", "protocol:user:pa%40ss%40word@host"),
+    ],
+)
+def test_transform_connection_string(connection_string, expected):
+    result = transform_connection_string(connection_string)
+    assert result == expected