Modify group_sub_entities in TokenClassification Pipeline to support label with "-"
Author: eshoyuan
Pull request: yes

# What does this PR do?

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This PR provides a bug fix for the `group_sub_entities` function within the NER pipeline. Previously, the function split entities on every dash (`-`), which led to incorrect parsing of entities that inherently contain a dash in their names. The code change ensures that only the first dash is considered for splitting, preserving the integrity of the entity names.

## Before submitting
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## Who can review?

- pipelines: @Narsil


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Comments:
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