Add support for snapshot testing (#88323)

* Add support for snapshot testing

* Use snapshots in Elgato diagnostics test

* Use snapshots in Elgato sensor test

* Fix flake8 warning

* Slightly improve serialized output

* Remove snapshot naming in elgato sensor tests

* Improve snapshoting of via_device_id in device registry item

* Update pylint typehints plugin for snapshot fixture typing

* Use snapshots in Elgato configflow test

* Use snapshots in Bluetooth repair issue tests

pylint/plugins/hass_enforce_type_hints.py

@@ -134,6 +134,7 @@ _TEST_FIXTURES: dict[str, list[str] | str] = {
     "recorder_db_url": "str",
     "recorder_mock": "Recorder",
     "requests_mock": "requests_mock.Mocker",
+    "snapshot": "SnapshotAssertion",
     "tmp_path": "Path",
 }
 _TEST_FUNCTION_MATCH = TypeHintMatch(