fix: correct google analytics env

[karelvuong]

Description

Fixes env var for Google Analytics in docs as it didn't match actual env var used in codebase (NEXT_PUBLIC_GA_MEASUREMENT_ID).

Related Issues

n/a

Checklist

• My code follows the code style of this project.
• I have performed a self-review of my code.
• I have commented my code, particularly in hard-to-understand areas.
• I have updated the documentation, if necessary.
• I have added tests that prove my fix is effective or my feature works.
• New and existing tests pass locally with my changes.

Screenshots (if applicable)

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After

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[haydenbleasel]

nice one @karelvuong - thank you!

[github-actions]

🚀 PR was released in v5.0.3 🚀