Correct weight refund in ds-chain-extension

[Dinonard]

Pull Request Summary

Removes unwrap() from dapps-staking chain-extension and replaces it with an exhaustive result check.

[github-actions[bot]]

Package	Line Rate	Branch Rate	Health
precompiles/sr25519/src	78%	0%	➖
precompiles/utils/macro/src	0%	0%	❌
frame/collator-selection/src	89%	0%	✔
frame/pallet-xvm/src/pallet	37%	0%	❌
frame/xc-asset-config/src	88%	0%	✔
precompiles/xcm/src	80%	0%	➖
precompiles/xvm/src	71%	0%	➖
precompiles/utils/src	84%	0%	✔
precompiles/substrate-ecdsa/src	78%	0%	➖
chain-extensions/trait/src	0%	0%	❌
chain-extensions/rmrk/src	0%	0%	❌
chain-extensions/dapps-staking/src	0%	0%	❌
frame/custom-signatures/src	81%	0%	✔
chain-extensions/types/dapps-staking/src	0%	0%	❌
precompiles/utils/macro/tests	100%	0%	✔
frame/pallet-xvm/src	9%	0%	❌
frame/dapps-staking/src	94%	0%	✔
frame/vesting/src	87%	0%	✔
primitives/xcm/src	88%	0%	✔
frame/dapps-staking/src/pallet	90%	0%	✔
frame/pallet-xcm/src	81%	0%	✔
precompiles/assets-erc20/src	91%	0%	✔
chain-extensions/types/xvm/src	0%	0%	❌
precompiles/utils/src/data	72%	0%	➖
frame/block-reward/src	96%	0%	✔
precompiles/dapps-staking/src	95%	0%	✔
chain-extensions/xvm/src	0%	0%	❌
chain-extensions/types/rmrk/src	0%	0%	❌
contracts/xvm/src	0%	0%	❌
Summary	81% (8402 / 10428)	0% (0 / 0)	✔

Minimum allowed line rate is 60%