Add OptionsFlow helper class (#82531)

* Add OptionsFlow helper classes

* More integrations

* Adjust SchemaOptionsFlowHandler

* Use single class

* Simplify access to options

* Reduce PR

* Make _options private

* Add test

tests/test_config_entries.py

@@ -3426,3 +3426,23 @@ async def test_async_wait_component_startup(hass: HomeAssistant):
 
     # The component has been loaded
     assert "test" in hass.config.components
+
+
+async def test_options_flow_options_not_mutated() -> None:
+    """Test that OptionsFlowWithConfigEntry doesn't mutate entry options."""
+    entry = MockConfigEntry(
+        domain="test",
+        data={"first": True},
+        options={"sub_dict": {"1": "one"}, "sub_list": ["one"]},
+    )
+
+    options_flow = config_entries.OptionsFlowWithConfigEntry(entry)
+
+    options_flow._options["sub_dict"]["2"] = "two"
+    options_flow._options["sub_list"].append("two")
+
+    assert options_flow._options == {
+        "sub_dict": {"1": "one", "2": "two"},
+        "sub_list": ["one", "two"],
+    }
+    assert entry.options == {"sub_dict": {"1": "one"}, "sub_list": ["one"]}