Silence nltk downloader

[jcgiuffrida]

Description

The nltk downloader prints unnecessarily to the console unless it is set to quiet=True. Because it uses print, it cannot be silenced using logging. The GlobalsHelper does not set quiet=True, so every project that uses llama_index.core.utils has messages like this printing to the console, all the time:

>>> from llama_index import core
[nltk_data] Downloading package punkt_tab to
[nltk_data]     /home/my_project/nltk_data...
[nltk_data]   Package punkt_tab is already up-to-date!

Type of Change

• Bug fix (non-breaking change which fixes an issue)

How Has This Been Tested?

• I believe this change is already covered by existing unit tests

Checklist:

• I have performed a self-review of my own code
• My changes generate no new warnings