[lib] Include specialRole field in RoleInfo for future clients

Summary: We include the specialRole field in RoleInfo based on shouldIncludeSpecialRoleFieldInRoles which is determined by a code version check.

Test Plan:
Hard coded shouldIncludeSpecialRoleFieldInRoles to true/false and observed that the specialRole field was included/excluded:

shouldIncludeSpecialRoleFieldInRoles = true:

shouldIncludeSpecialRoleFieldInRoles = false:

Reviewers: ginsu, tomek

Reviewed By: ginsu

Subscribers: ashoat

Differential Revision: https://phab.comm.dev/D10995