JS Linting: Restructure content on VSCode extensions

[MaoShizhong]

Because

In #27962 I only made small structural changes to make the JS Linting lesson match our lesson style guide, but the contents was largely unchanged.

Quite a few times (before and after), learners have been confused as to whether they should install the npm packages and/or use the VSCode extensions and why. It appears to come from the ESLint and Prettier sections mentioning both then only later does it talk about the need to install npm packages and the extensions being additional IDE integration tools for personal convenience.

The info about extensions can be taken out of the ESLint/Prettier sections so they only talk about the npm packages. At the end, there can be a new IDE extensions section which will hopefully make the lessons' point much clearer and easier to follow.

This PR

• Removes VSC extension information from the Linting and Formatting sections
• Rewrites the VSC extension note box as a dedicated lesson level 3 section
• Fixes and link fragments as appropriate

Issue

Closes #29499

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