FreeBalance as default dapp-staking reward destination

[Dinonard]

Pull Request Summary

Changes default reward destination from StakeBalance to FreeBalance for dApp staking.
Applies to all runtimes.

Check list

• added or updated unit tests
• updated spec version
• updated semver

[ashutoshvarma]

CI is failing due to some issue in mock runtime.
Also why are we changing the default?

[Dinonard]

CI is failing due to some issue in mock runtime. Also why are we changing the default?

It was requested by BizDev & UI team, due to integration with the Ledger.
They will not support set_reward_destination for old devices, so it would be unfair to force users to keep restaking, without the possibility to claim into free balance.

[github-actions]

Package	Line Rate	Branch Rate	Health
chain-extensions/pallet-assets/src	0%	0%	❌
chain-extensions/types/assets/src	0%	0%	❌
pallets/block-reward/src	85%	0%	✔
pallets/ethereum-checked/src	69%	0%	➖
pallets/pallet-xcm/src	54%	0%	➖
chain-extensions/xvm/src	0%	0%	❌
pallets/pallet-xvm/src	5%	0%	❌
chain-extensions/dapps-staking/src	0%	0%	❌
pallets/contracts-migration/src	0%	0%	❌
precompiles/dapps-staking/src	93%	0%	✔
precompiles/sr25519/src	79%	0%	➖
precompiles/utils/src	69%	0%	➖
pallets/xc-asset-config/src	54%	0%	➖
chain-extensions/types/xvm/src	0%	0%	❌
precompiles/utils/macro/src	0%	0%	❌
pallets/dapps-staking/src	82%	0%	✔
precompiles/xcm/src	85%	0%	✔
pallets/custom-signatures/src	52%	0%	➖
precompiles/xvm/src	61%	0%	➖
primitives/src	72%	0%	➖
primitives/src/xcm	70%	0%	➖
precompiles/assets-erc20/src	76%	0%	➖
chain-extensions/types/dapps-staking/src	0%	0%	❌
pallets/dapps-staking/src/pallet	87%	0%	✔
pallets/pallet-xvm/src/pallet	8%	0%	❌
precompiles/substrate-ecdsa/src	78%	0%	➖
pallets/collator-selection/src	70%	0%	➖
Summary	55% (2243 / 4061)	0% (0 / 0)	➖

Minimum allowed line rate is 50%

[ashutoshvarma]

LGTM

[shaunxw]

Looks good!