Settings USER_OPERATION_ERROR_FEATURE_UNSUPPORTED

If private space creation fails due to a lack of system features, we
returned USER_OPERATION_ERROR_PRIVATE_PROFILE. This return value was
overly specific; we generalize it for all applicable user types as
USER_OPERATION_ERROR_FEATURE_UNSUPPORTED. The caller knows what type of
user they were trying to create anyway.

So we update the constant to the new name.

Test: N/A. Just a renamed constant.
Bug: 394178333
Flag: EXEMPT refactor
Change-Id: I6040f3f31a299765823d8caabdd662f1c2523497