staking: Remove `SessionInterface` supertrait
@@ -653,7 +653,7 @@ impl<AccountId, Balance: HasCompact + Zero> UnappliedSlash<AccountId, Balance> {
/// Means for interacting with a specialized version of the `session` trait.
///
/// This is needed because `Staking` sets the `ValidatorIdOf` of the `pallet_session::Config`
-pub trait SessionInterface<AccountId>: frame_system::Config {
+pub trait SessionInterface<AccountId> {
/// Disable the validator at the given index, returns `false` if the validator was already
/// disabled or the index is out of bounds.
fn disable_validator(validator_index: u32) -> bool;
