🚨 🚨 🚨 Fix CvT parameter initialization

[mathieujouffroy]

What does this PR do?

This PR aims to rectify the difference in parameter initialization between the HF implementation and the original implementation (microsoft).

• Initializes torch dense layer weights with trunc_normal instead of normal.
• Initializes cls_token with trunc_normal

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As discussed @amyeroberts here's the PR regarding the changes for the CvT pytorch model 😊

[HuggingFaceDocBuilderDev]

The documentation is not available anymore as the PR was closed or merged.

[amyeroberts]

LGTM 👍 Thanks for the fix! Sorry, I was going through my github notifications and didn't see it was merged. Still thank you for the fix though :)

[sgugger]

For the records, this is the same thing as in #19341