More React Concepts: update React Context documentation link and remove additional resources section from relevant lessons

[sameeksha-dalvi]

Because

This PR updates the React Context documentation link in assignment and removes the additional resources section from relevant lessons.

This PR

• Update the assignment to link to the React Context documentation in the Managing State with the Context API lesson
• Remove the additional resources section from the Managing State with the Context API lesson
• Remove the additional resources section from the Reducing State lesson

Issue

Closes #30919

Additional Information

Pull Request Requirements

• I have thoroughly read and understand The Odin Project curriculum contributing guide
• The title of this PR follows the location of change: brief description of change format, e.g. Intro to HTML and CSS lesson: Fix link text
• The Because section summarizes the reason for this PR
• The This PR section has a bullet point list describing the changes in this PR
• If this PR addresses an open issue, it is linked in the Issue section
• If any lesson files are included in this PR, they have been previewed with the Markdown preview tool to ensure it is formatted correctly
• If any lesson files are included in this PR, they follow the Layout Style Guide