Resolve no-shadow eslint errors

[moorscode]

Summary

This PR can be summarized in the following changelog entry:

• N/A

Relevant technical choices:

• Renamed the variables that were already declared in a higher scope

Test instructions

This PR can be tested by following these steps:

• Make sure the functionality of the touched functions still works
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  • Onboarding wizard steps
  • Onboarding wizard AJAX requests (save/load data)
  • Collapsible headings

Fixes #

[abotteram]

CR :construction:

[Dieterrr]

CR done 👍

[abotteram]

Acceptance :+1: