Cohort Permission Improvements

Before: Users with Edit Cohort permissions but without Create Cohort permissions were blocked from saving cohorts or inspecting users from report breakdowns, even though these actions should be allowed.

Now: Permission handling now properly separates Save Cohort from Update existing cohort actions. Users with edit permissions can now update existing cohorts and inspect users without needing full create permissions.

The Result: Users with "Edit Cohort" permissions can now successfully update existing cohorts and access report breakdowns independently of "Create" permissions