Optimize how ReadViews are fetched

[acerone85]

Following #2666, the ReadViewProvider is not optimized to retrieve the view stored in the graphql request data.
We should optimize the code to retrieve the least amount of views from the DB.

(Below is a list of proposed optimizations, it will be updated in the future)

Proposed optimizations:

• The first time we check a height in the RequiredFuelBlockHeight extension, we could retrieve it from the RequiredBlockHeightSubscriptionHandle, which will need to be adapted to keep track of the latest seen BlockHeight. This way, there is no need to fetch the database view in async_graphql extensions.