Update type hints for Twisted 23.8.0 changes

[wRAR]

Twisted 23.8.0 has improved and fixed type hints around deferreds so now mypy prints some errors:

scrapy/core/scraper.py:184: error: Argument 1 to "addErrback" of "Deferred" has incompatible type "Callable[[Failure, Request, Response, Spider], None]"; expected "Callable[[Failure, Request, Response, Spider], Deferred[<nothing>]]"  [arg-type]
scrapy/core/scraper.py:184: error: Argument 3 to "addErrback" of "Deferred" has incompatible type "Response | Failure"; expected "Response"  [arg-type]
scrapy/core/scraper.py:185: error: Argument 1 to "addCallback" of "Deferred" has incompatible type "Callable[[Iterable[Any] | AsyncIterable[Any], Request, Response, Spider], Deferred[Any]]"; expected "Callable[[Any, Request, Response, Spider], Failure]"  [arg-type]
scrapy/core/scraper.py:185: error: Argument 3 to "addCallback" of "Deferred" has incompatible type "Response | Failure"; expected "Response"  [arg-type]
scrapy/core/downloader/__init__.py:157: error: Need type annotation for "deferred"  [var-annotated]
scrapy/core/engine.py:223: error: Incompatible return value type (got "None", expected "Failure")  [return-value]
scrapy/core/engine.py:300: error: Argument 1 to "addBoth" of "Deferred" has incompatible type "Callable[[Response | Request, Request], Deferred[Any] | Response]"; expected "Callable[[Any | Failure, Request], Failure]"  [arg-type]

(I omitted some unhelpful mypy tips). This needs reviewing, as it's not clear at the first glance if we have any problems with code and/or type hints.

[wRAR]

I'm fine with not fixing it when we re-enable that Twisted version in 2.10.2 and letting the test fail for the 2.10 branch.