Fix/issue 270 estimated order amount multicurrency

[alexiglesias31]

All Submissions:

• [x] Does your code follow the Extendables standards?
• [x] Have you written new tests for your changes, as applicable?
• [x] Have you successfully run tests with your changes locally?

Changes proposed in this Pull Request:

Disable the estimated order amount if the currency is not the default currency for the region.

How to test the changes in this Pull Request:

1. Install a built version of this branch and setup the amazon plugin to Europe region.
2. Install the plugin FOX - Currency Switcher Professional for WooCommerce.
3. Estimated order amount should be set when the currency is EUR but should not be set when the currency is USD.
4. The checkout can be completed without issues.

Other information:

• [x] Have you checked to ensure there aren't other open Pull Requests for the same update/change?

Changelog entry

Fix - Issue with estimated order amount and multi-currency.

[alexiglesias31]

I didn't know about that, yes, I tested with an empty string and works as well 👍

P.D: 🤔, giving a second thought to this, it doesn't feel correct to me that the estimated order amount is empty when the currency is different. I would find more intuitive to pass the converted amount rather than an empty string.

[alexiglesias31]

Providing a new approach, instead of set the total as empty, moving back to return an empty string on the estimated_order_amount, but now adding some checks in the JS code so the parameter is not set when is empty.

[alexiglesias31]

@dpanta94 asking CR again, since the EOA was still being calculated on blocks.

[alexiglesias31]

I think so 😄, EOA is not used on the JS related to classics