Base native currency price for dApp Staking

[Dinonard]

Pull Request Summary

Fixes an issue with threshold calculation in dApp staking.

The issue happens because the formula for tier threshold update did not account for threshold value saturation. As ASTR price increased, so did the number of available slots, and as a result, thresholds saturated at the minimum possible value. Number of slots could keep increasing, while the thresholds remained the same.

But as ASTR price dropped, this brought a negative change in the number of slots. Since number of slots was way larger than the base number of slots, this seemed as a larger change that it was supposed to be, in respect to the current threshold.

This fix changes the way threshold is calculated so that the new_number_of_slots is always compared to the base_number_of_slots. This way ensures thresholds are always updated in respect to what the baseline is.

Note

• issue was reproduced first using the new unit test
• fix was verified on a chain fork using chopsticks

[github-actions[bot]]

Package	Line Rate	Branch Rate	Health
pallets/dapp-staking-migration/src	0%	0%	❌
pallets/oracle-benchmarks/src	0%	0%	❌
precompiles/dispatch-lockdrop/src	86%	0%	✔
primitives/src	61%	0%	➖
pallets/ethereum-checked/src	79%	0%	➖
pallets/dynamic-evm-base-fee/src	92%	0%	✔
chain-extensions/types/unified-accounts/src	0%	0%	❌
precompiles/dapp-staking-v3/src	90%	0%	✔
pallets/unified-accounts/src	86%	0%	✔
precompiles/dapp-staking-v3/src/test	0%	0%	❌
precompiles/unified-accounts/src	100%	0%	✔
chain-extensions/pallet-assets/src	56%	0%	➖
chain-extensions/types/assets/src	0%	0%	❌
pallets/collator-selection/src	92%	0%	✔
pallets/price-aggregator/src	72%	0%	➖
pallets/astar-xcm-benchmarks/src/fungible	100%	0%	✔
pallets/dapp-staking-v3/src/benchmarking	98%	0%	✔
pallets/static-price-provider/src	52%	0%	➖
precompiles/xcm/src	73%	0%	➖
pallets/astar-xcm-benchmarks/src/generic	100%	0%	✔
pallets/dapp-staking-v3/src	92%	0%	✔
precompiles/substrate-ecdsa/src	74%	0%	➖
chain-extensions/types/xvm/src	0%	0%	❌
precompiles/assets-erc20/src	81%	0%	✔
pallets/dapp-staking-v3/src/test	0%	0%	❌
pallets/xc-asset-config/src	64%	0%	➖
pallets/inflation/src	83%	0%	✔
pallets/dapp-staking-v3/rpc/runtime-api/src	0%	0%	❌
precompiles/sr25519/src	64%	0%	➖
pallets/astar-xcm-benchmarks/src	88%	0%	✔
primitives/src/xcm	64%	0%	➖
precompiles/xvm/src	75%	0%	➖
pallets/xvm/src	54%	0%	➖
chain-extensions/xvm/src	0%	0%	❌
chain-extensions/unified-accounts/src	0%	0%	❌
Summary	78% (3600 / 4635)	0% (0 / 0)	➖

Minimum allowed line rate is 50%