missing parts in PayPal Express Checkout flow

[mkucmus]

📚 Documentation Issue Report

Describe the bug

• In general, everything is ok but they mentioned a few points:
  An incorrect PayPal flow was taking place within the current implementation due to a missing parameter. This refers to the "commit" parameter which defines which flow the user proceeds with. Within the meeting, it was clarified that the "commit" parameter should be set to the "false" value, so that the "Continue" button is displayed within the PayPal checkout flow. Here you can find more information regarding the "commit" parameter For this issue a solution was clarified
• It was clarified that the checkout flow that was taking place at the moment (in the end of the checkout (once the order was reviewed already by the customer on Paypal side) and the "Jetzt zahlungspflichtig bestellen" button is clicked, the user was once again redirected to PayPal). According to the feedback from PayPal, the redirection mentioned should not take place and instead the transaction should be initialized and the customer should be redirected to the "Thank you" page.

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To Reproduce

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Additional context

slack discussion

[mkucmus]

the PayPal payment provider has been described in #1641

[mkucmus]

The current status:

the headless integration works well together with https://github.com/shopware/SwagPaypal as a payment provider ✅

SaaS environment cannot be tested properly as it has some issues: ⚠

• the sandbox client id is hardcoded and cannot be changed, developer cannot obtain it without accessing the private repository
• the connected account sandbox mode is not taken into account
• there is no way to disconnect an account once it's setup without patching a system config via admin API
• it is not clear what test/sandbox mode is: once the setup is complete, while creating a paypal order, the developer faces INVALID_CREDENTIALS error because of some failing conditions in the code which says that sandbox mode cannot be activate on a live production mode

[mkucmus]

The issues have been reported in the extension's internal repository.