fix: remove redundant single-component use reqwest import

Fixes clippy::single_component_path_imports lint error in
test_sse_concurrent_streams.rs.

Author: alexhancock

crates/rmcp/tests/test_sse_concurrent_streams.rs

@@ -15,7 +15,6 @@ use std::sync::Arc;
 use std::time::Duration;
 
 use futures::StreamExt;
-use reqwest;
 use rmcp::{
     RoleServer, ServerHandler,
     model::{Implementation, ProtocolVersion, ServerCapabilities, ServerInfo, ToolsCapability},