Avoid dummy token in PLD to optimize performance
Author: ofirzaf
Pull request: yes

# What does this PR do?
Current PLD implementation adds a dummy token in case there is no match found in the prompt to avoid issues. In previous PR #28508 the code was fixed to handle zero candidate tokens so there is no need for the dummy token in PLD now. Not inserting this additional token can accelerate PDL on weaker HW where doing inference with the target with 2 tokens is significantly slower than doing inference with 1 token. 

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@gante

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Comments:
@gante I am unable to share my measurements since I am working on HW that wasn't released yet. Is it blocking the merge?

@ofirzaf no :) I'm going to merge the PR

In any case, if you have the script to reproduce your measurements, it would be a nice addition