polish(payments-next): remove unused code, clean up linting rules

[david1alvarez]

Because:

• This code was not used anywhere
• payments-next was failing the lint check due to rules, rather than tangible issues

This commit:

• removes unused code
• updates payments next eslintrc rules

Closes #N/A

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• If applicable, I have modified or added tests which pass locally.
• I have added necessary documentation (if appropriate).
• I have verified that my changes render correctly in RTL (if appropriate).

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