Typo fix

[Suyog007]

There is a typographical error that needs correction in the codebase. Some of the typo error are:

• settlement in https://github.com/ventur23/localcoin/blob/development/contracts/campaign_management/src/lib.rs#L143
• associated in https://github.com/venture23/localcoin/blob/development/contracts/issuance_management/src/lib.rs#L195