membership: Fix NotMember error

[vatsa287]

Fixes: #454 (temporarily)

The current implementation of IsMember throws below error, for all extrinsics where is_member check would be required.

vatsa@Shreevatsas-MacBook-Pro cord % cargo build --release --features=runtime-benchmarks
    Finished release [optimized] target(s) in 2.27s
vatsa@Shreevatsas-MacBook-Pro cord % ./target/release/cord benchmark pallet --chain=dev --pallet=pallet_membership --extrinsic="*"
2024-05-27 14:59:41 Starting benchmark: pallet_membership::add_member    
2024-05-27 14:59:41 panicked at /Users/vatsa/cord/pallets/membership/src/benchmarking.rs:51:9:
Expected Ok(_). Got Err(
    DispatchErrorWithPostInfo {
        post_info: PostDispatchInfo {
            actual_weight: None,
            pays_fee: Pays::Yes,
        },
        error: Module(
            ModuleError {
                index: 23,
                error: [
                    1,
                    0,
                    0,
                    0,
                ],
                message: Some(
                    "NotMember",
                ),
            },
        ),
    },
)    
Error: Input("Error executing and verifying runtime benchmark: Execution aborted due to trap: wasm trap: wasm `unreachable` instruction executed\nWASM backtrace:\nerror while executing at wasm backtrace:\n    0: 0x3e544f - <unknown>!rust_begin_unwind\n    1: 0x3a5209 - <unknown>!core::panicking::panic_fmt::he98e37cb800cf5e7\n    2: 0x2a9803 - <unknown>!core::ops::function::FnOnce::call_once{{vtable.shim}}::h885e1a40413f689e\n    3: 0x196e01 - <unknown>!pallet_membership::benchmarking::<impl frame_benchmarking::utils::Benchmarking for pallet_membership::pallet::Pallet<T,I>>::run_benchmark::h7144304981d536cc\n    4: 0x2d654 - <unknown>!<cord_runtime::Runtime as frame_benchmarking::utils::runtime_decl_for_benchmark::BenchmarkV1<sp_runtime::generic::block::Block<sp_runtime::generic::header::Header<u32,sp_runtime::traits::BlakeTwo256>,sp_runtime::generic::unchecked_extrinsic::UncheckedExtrinsic<sp_runtime::multiaddress::MultiAddress<<<sp_runtime::MultiSignature as sp_runtime::traits::Verify>::Signer as sp_runtime::traits::IdentifyAccount>::AccountId,()>,cord_runtime::RuntimeCall,sp_runtime::MultiSignature,(pallet_network_membership::CheckNetworkMembership<cord_runtime::Runtime>,frame_system::extensions::check_non_zero_sender::CheckNonZeroSender<cord_runtime::Runtime>,frame_system::extensions::check_spec_version::CheckSpecVersion<cord_runtime::Runtime>,frame_system::extensions::check_tx_version::CheckTxVersion<cord_runtime::Runtime>,frame_system::extensions::check_genesis::CheckGenesis<cord_runtime::Runtime>,frame_system::extensions::check_mortality::CheckMortality<cord_runtime::Runtime>,frame_system::extensions::check_nonce::CheckNonce<cord_runtime::Runtime>,frame_system::extensions::check_weight::CheckWeight<cord_runtime::Runtime>)>>>>::dispatch_benchmark::hc771e433e1131f7a\n    5: 0x26d6f6 - <unknown>!Benchmark_dispatch_benchmark")

Should this check be entirely removed since the check is based Members list present in NetworkMembership pallet.
Or, change the error code.
A) Question is Members lists of both Membership & NetworkMembership is same?
B) When is Membership used, as it is not part of initial_config file?
@amarts @smohan-dw

[smohan-dw]

#456 should fix this, as I have removed the extra session key check to nominate a new member. The membership pallet governs the council (governance) members, while network membership deals with members' transaction authorizations. We can close this.

[vatsa287]

Thanks. Will close as completed.