fix: replace var keyword with const/let

[JulianaSau]

Replaced the var keyword with let/const depending on the context

Fixes #11481

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Code Climate has analyzed commit 47261388 and detected 0 issues on this pull request.

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This pull request generated screenshots of many common pages in the running app. You should be able to download and view them here: https://github.com/publiclab/plots2/suites/8836943984/artifacts/402733778

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This pull request generated screenshots of many common pages in the running app. You should be able to download and view them here: https://github.com/publiclab/plots2/suites/8836943984/artifacts/403818199

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[TildaDares]

Congratulations on merging your PR @JulianaSau 🎉

[JulianaSau]

Congratulations on merging your PR @JulianaSau 🎉

Thank you. I'm happy to be a contributor to this project😁