[Content Reduction] Remove redundant Git setup instructions between `vi-prerequisites.md` and `vi-github-and-markdown.md`

[Saby-Bishops]

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• This issue is related to the Virtual Interns First Steps document or Planet User Manual.
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URL to the MDwiki page containing the problem

https://github.com/open-learning-exchange/open-learning-exchange.github.io/blob/master/pages/vi/vi-github-and-markdown.md

Problem

The guide has redundant instructions. The process of installing Git is detailed in vi-prerequisites.md, but vi-github-and-markdown.md repeats the command to install it. This creates confusion for a new intern who has already followed the prerequisites, making them think they may have missed a separate, specific step.

Screenshots (when necessary)

Proposed solution(s)

Remove the Git installation instructions from the beginning of vi-github-and-markdown.md and replace them with a sentence that links back to the prerequisite step. For example: "Before you begin: Ensure you have completed the Software Prerequisites, including installing and configuring Git." This creates a logical flow and eliminates repetition.