sp-api: Put frame-metadata behind some feature (#14398)

* sp-api: Put `frame-metadata` behind some feature

Closes: https://github.com/paritytech/substrate/issues/14296

* ".git/.scripts/commands/fmt/fmt.sh"

* Review feedback

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Co-authored-by: command-bot <>

substrate/primitives/api/src/lib.rs

@@ -84,6 +84,7 @@ use sp_core::OpaqueMetadata;
 #[doc(hidden)]
 pub use sp_core::{offchain, ExecutionContext};
 #[doc(hidden)]
+#[cfg(feature = "frame-metadata")]
 pub use sp_metadata_ir::{self as metadata_ir, frame_metadata as metadata};
 #[doc(hidden)]
 #[cfg(feature = "std")]