fix: guard dedupe() against empty extractBests result when processor empties the query

[koteshyelamati]

Fixes #94

Problem

dedupe() crashes with ValueError: max() arg is an empty sequence when any item in the input list is reduced to an empty string by the default processor (utils.full_process).

from thefuzz.process import dedupe
dedupe(['###', 'apple', 'apple pie'])
# ValueError: max() arg is an empty sequence

When full_process('###') returns '', every comparison scores 0, so extractBests returns [] (below the 70 threshold). The subsequent max([]) then raises ValueError.

Fix

Guard the max() call: if matches is empty, add item itself to deduped (treating it as its own cluster):

if matches:
    deduped.add(max(matches, key=lambda x: (len(x[0]), x[0]))[0])
else:
    deduped.add(item)

This preserves the existing warning (already emitted by extractBests) and keeps items that cannot be fuzzy-matched as their own entry in the deduplicated output.