Seeing the subject line "Preventing Use of uninitialized value", my first thought was

{
    use warnings FATAL => qw(uninitialized);
    ...
}
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which would ultimately prevent uninitialized values to be used :-P

OTOH, that is not what you want, since you make clear you just don't want to be warned about it. The (short term) solution for you is simply

{
    no warnings "uninitialized";
    ...
}
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On the third hand, of course, the best solution would be to find out, why these values are uninitialized and to do something about that… (Update: as already suggested by pryrt)