[e2e] Migrate multi-currency e2e tests to playwright

[reykjalin]

Description

In an effort to improve the maintainability of the multi-currency e2e tests we want to migrate them to Playwright. This should offer more reliability when running the tests.

The following tests will have to be migrated:

• tests/e2e/specs/wcpay/merchant/merchant-admin-multi-currency.spec.js
• tests/e2e/specs/wcpay/merchant/merchant-admin-multi-currency-on-boarding.spec.js
• tests/e2e/specs/wcpay/merchant/merchant-admin-multi-currency-setup.spec.js
• tests/e2e/specs/wcpay/shopper/shopper-checkout-multi-currency.spec.js

It may be worth it to split this into 2 issues (merchant/shopper) when we start working on this.

[bborman22]

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