Use map with captures.

@array = map { 
    m{
        \s*     # skip leading whitespace
        (       # then capture
            .*  # the longest possible substring
            \S  # that ends with a visible character
        )
    }x
} @array;
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This loses any array elements that contained nothing but whitespace. If you want to retain these elements as empty strings, insert |$ in your capture.