Bug: Feeder Pool withdraw when pool balance is low

[dimsome]

About

When redeeming LPtokens from a pool that is low in balance or if the withdrawer is the majority holder of the LPtokens, the normal single sided withdrawal does not work anymore. The user needs to withdraw proportionally.

Issue

Feeder Pool page: https://mstable.app/#/musd/pools/0x4eaa01974b6594c0ee62ffd7fee56cf11e6af936

Cannot specify how many pooltokens should be used.

Steps

• [ ] Allow redemption based on Pooltokens, e.g. click on the amount to specify or allow amount to be entered in that field.
• [ ] Calculate the proportional output.
• [ ] Use redeemProportionality (https://etherscan.io/token/0x4eaa01974b6594c0ee62ffd7fee56cf11e6af936?a=0xa23F54e0BB57a6114D831c080823F5Fe2616CF98#writeProxyContract#F13)

https://dashboard.tenderly.co/dimsome/project/simulator/74b3cc5e-baae-407b-b2ad-f3e351f3be18