Consider using the bounds in the IntoProposal trait for into path bounds #267
Description
The current problem is that in pallet-briefs and pallet-grants i have to rebind the bounds of inputs for conversion to a project to match that of IntoProposal::convert_to_proposal this is obviously not ideal. Another issue surrounding this is we have 3 locations where max milestones is defined. Ofc this has been covered by the sanity tests but if we use the bound of the IntoProposal's associated types we dont have to do these checks.
Its a nice to have for sure