Use JsonSerializable for user_data

[Pijukatel]

Description

Use JsonSerializable type for user_data

Issues

• Closes: Update push_data annotations to use JsonSerializable type #1191

[Pijukatel]

It seems ok according to mypy like this and unit tests are passing as well, but I am not really sure about this though. As discussed here: https://github.com/apify/crawlee-python/pull/1086/files/a67d3b3b42d2a1d59923810fe6f17dabeea3e98b#r1995086090

there are some casts down the road when it comes to user data, which makes me unsure about type checking result.

[janbuchar]

The reason this is uncool is that crawlee puts its own stuff into user_data (more precisely user_data['__crawlee']), and this depends on it being a dictionary. Not sure if the platform would accept anything other than a dict, too...