Disable rustls' aws-lc-rs feature

When both the `ring` and `aws-lr-rs` features in `rustls` are enabled,
the rustls `CryptoProvider` installer from crate features no longer
works, as the provider to be used is ambiguous [1].

This is the default configuration and feature set that other
dependencies like `reqwest` are using.

[1]: https://docs.rs/rustls/latest/src/rustls/crypto/mod.rs.html#261-282

Cargo.toml

@@ -27,7 +27,9 @@ rand = { version = "0.8.5", optional = true }
 reqwest = { version = "0.12.2", optional = true, default-features = false, features = [
   "json",
 ] }
-rustls = { version = "0.23.4", optional = true }
+rustls = { version = "0.23.4", optional = true, default-features = false, features = [
+  "ring",
+] }
 serde = { version = "1.0.171", features = ["derive"], optional = true }
 serde_json = { version = "1.0.103", optional = true }
 thiserror = { version = "1.0.43", optional = true }