[Staging] Remove env variable referencing my-site

[MayankBansal12]

Description

As part of my-site deprecation, staging env variables in skill-tree-frontend referencing my-site needs to be removed.
There's only one variable currently referencing my-site.

• Issue: Deprecate and retire my-site todo-action-items#318
• PR removing reference: Create new component InputField for input website-my#167

Required Action

• Remove NEXT_PUBLIC_MY_SITE_URL from env variables in staging enviroment
• Look out for any other variables/configurations referencing my-site

Required Change

• Remove env variable NEXT_PUBLIC_MY_SITE_URL

[prakashchoudhary07]

@MayankBansal12 Have removed NEXT_PUBLIC_MY_SITE_URL, ENV variable. Could not find any other variable refering my-site
Thank you for the details