Fix - site name too long error

[dpanta94]

All Submissions:

• [x] Does your code follow the Extendables standards?
• [ ] 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:

Closes woo#138 .

How to test the changes in this Pull Request:

1. payments should not fail even when the site name is more than 50 characters long

Other information:

This PR includes the fixes introduced here. The difference is that is created from main and it also amends this request https://app.clickup.com/t/27phubt

merchantStoreName is an optional field only used to overwrite what the merchant has already configured during his Merchant account set up. @see https://developer.amazon.com/docs/amazon-pay-checkout/buyer-communication.html @see https://developer.amazon.com/docs/amazon-pay-api-v2/charge.html#type-merchantmetadata

We could completely skip setting it, but for backwards compatibility we include it for sites with a site name equal or less than 50 characters.

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

[dpanta94]

Opened in woo repo pull#164

[dpanta94]

accepted in woo repo