audit: Voting Power Not Easily Estimated in User Interface

[Orland0x]

In the current implementation, estimating the voting power for each voting strategy of a space before casting a vote is challenging. The issue lies with the getVotingPower() method in the voting strategy contracts, which is not a view function and can perform state changes due to the potential need for resolving the timestamp, in CompVotingStrategy and OZVotesVotingStrategy.
This makes it hard for the user interface to call the function for estimation purposes without sending a transaction.