Fix pswap-distribution benchmark

[wer1st]

pswap-distribution benchmark (not test) panics.

How to reproduce:

cargo run --bin framenode --features private-net,runtime-benchmarks,ready-to-test benchmark pallet --chain=local  --execution=native --wasm-execution=compiled --pallet pswap_distribution --extrinsic "*" --steps 2 --repeat 1 --output  ./benches

Error:

Thread 'main' panicked at 'assertion failed: Assets::<T>::free_balance(&PSWAP.into(), &liquidity_provider).unwrap() >\n    balance!(0)', /home/wer/workspace/sora2-network/pallets/pswap-distribution/benchmarking/src/lib.rs:199

2023-12-14 16:34:21 Evicting failed runtime instance error=Runtime panicked: assertion failed: Assets::<T>::free_balance(&PSWAP.into(), &liquidity_provider).unwrap() >\n    balance!(0)
Error: Input("Error executing and verifying runtime benchmark: Runtime panicked: assertion failed: Assets::<T>::free_balance(&PSWAP.into(), &liquidity_provider).unwrap() >\\n    balance!(0)")