units: remove the restart limit on the modprobe@.service
    
    They are various cases where the same module might be repeatedly
    loaded in a short time frame, for example if a service depending on a
    module keep restarting, or if many instances of such service get
    started at the same time. If this happend the modprobe@.service
    instance will be marked as failed because it hit the restart limit.
    
    Overall it doesn't seems to make much sense to have a restart limit on
    the modprobe service so just disable it.
    
    Fixes: #23742
    (cherry picked from commit 9625350e5381a68c1179ae4581e7586c206663e1)