When members with a permanent exemption from shift register to shifts, those shifts should me marked automatically as solidarity shifts.

[Theophile-Madet]

See request here, from Vicky

• The check if the member has a permanent exemption should be done when the attendance is registered, not when the member registers to the slot.
• The member should get a warning when registering that the shift will be marked as solidarity
• This should only apply to members that already have 4 banked shifts, on top of being permanently exempted.