Replace REQUEST_BURN_SHARES_ROLE with REQUEST_BURN_MY_STETH_ROLE for All Staking Modules

[mkurayan]

Summary

Currently, all staking modules have the REQUEST_BURN_SHARES_ROLE role in the Burner contract, which allows the caller to lock stETH from any address that has pre-approved an amount of stETH for burning, but staking modules must only lock stETH from their contract address. Therefore, staking modules can use the less powerful REQUEST_BURN_MY_STETH_ROLE role.

Problem

The 'REQUEST_BURN_SHARES_ROLE' grants staking modules excessive permissions beyond what is necessary, violating the principle of granting only the minimum required permissions.

Implementation

It is recommended to remove the REQUEST_BURN_SHARES_ROLE from all staking modules and grant them the REQUEST_BURN_MY_STETH_ROLE instead.

This change will require minimal contract code modifications but will enhance module isolation and protocol security.

Guidelines

• I agree to follow Code of Conduct.
• I have read Lido Contribution Guide.