Enable clippy::useless_conversion (#8724)

This PR enables the
[`clippy::useless_conversion`](https://rust-lang.github.io/rust-clippy/master/index.html#/useless_conversion)
rule and fixes the outstanding violations.

Release Notes:

- N/A

crates/lsp/src/lsp.rs

@@ -977,7 +977,7 @@ impl LanguageServer {
                     Self::notify_internal::<notification::Cancel>(
                         &outbound_tx,
                         CancelParams {
-                            id: NumberOrString::Number(id as i32),
+                            id: NumberOrString::Number(id),
                         },
                     )
                     .log_err();