restructure paymentTab.js

[luixxiul]

Test plan

#8237 (comment)

1. Open about:preferences#sync
2. Make sure "beta" is aligned top
3. Open about:preferences#payments
4. Make sure the labels appear the same row
5. Make sure the switches and the labels are aligned exactly like Restructuring paymentsTab.js #7751

Ping @luixxiul for fixes in case the style becomes broken.

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Refactored into this:

• Any related issues: Fixed style on ledger settings UI area to match 1.0 features/changes #7348 Payment UI 1.0 #7532

[luixxiul]

This regressed due to #8198 #8121

[luixxiul]

I'm going to address the issue by creating custom sectionTitle components, with Aphrodite.