chore: Simplified error qualifier types

[0x676e67]

This pull request focuses on refactoring the error handling in the src/client/http.rs file by consolidating the error types used throughout the code. The changes primarily involve replacing crate::Error with Error to streamline error management.

Key changes include:

Error handling refactor:

• src/client/http.rs: Updated various use statements to include Error from crate::error and removed redundant imports. [1] [2]
• src/client/http.rs: Modified the Config struct to use Option<Error> instead of Option<crate::Error>.
• src/client/http.rs: Updated the execute method in impl Client to return Result<Response, Error> instead of Result<Response, crate::Error>.
• src/client/http.rs: Changed the Error type in impl tower_service::Service<Request> for Client and impl tower_service::Service<Request> for &'_ Client to Error instead of crate::Error. [1] [2]
• src/client/http.rs: Refactored error handling in ClientMut, PendingInner, Pending, and PendingRequest to use Error instead of crate::Error. [1] [2] [3] [4] [5]