program: Expose check_manager_fee_info as pub for cross-program use

[aoikurokawa]

• Changes the visibility of check_manager_fee_info from pub(crate) to pub to allow external programs to reuse this validation helper.

[joncinque]

Thanks for your contribution -- I'm not against this PR, but is there a particular motivation for this change?

[aoikurokawa]

Thanks for taking a look @joncinque !
The motivation is that we'd like to use this check in our own program. Currently, since it's private, we'd have to duplicate the logic on our side. Making it public would allow us to import and reuse it directly, which helps keep things consistent and avoids maintaining a separate copy.

[joncinque]

Gotcha, sounds good!