AstraDB (+async) should use the request handler for correct management of 4xx and 5xx

[hemidactylus]

Contrary to the collection classes, the AstraDB and AsyncAstraDB classes have this in their request method:

responsebody = cast(API_RESPONSE, response.json())

i.e. unprotected json coercion regardless e.g. of HTTP 500 errors and the like. Thus, the user would see the error as an unparseable JSON.

Proposed solution:
the request methods should use the same request handler as done in the collection classes.

(thanks @nicoloboschi for bringing this up!)