This PR fixes an issue in the IDP auto-linking feature where user
searches were performed globally instead of being scoped to the current
organization context. This could result in IDP links being created for
users in unintended organizations.
# Which Problems Are Solved
When IDP auto-linking was enabled (by email or username), the system
would search for existing users across all organizations instead of
restricting the search to the current organization context.
# How the Problems Are Solved
Added organization scoping to all three auto-linking code paths