Add missing API client to function call arguments.

[evs-xsarus]

Thank you for creating this pull request! To make the best use of your and our time we created this checklist to get the best possible pull requests:

• [x ] The code is working on a plain Magento 2 installation.
• [ x] The code follows the PSR-2 code style.
• [ na] When an exception or error is logged the message is accompanied with some context, eg: Error when trying to get the payment status:
• [ na] Contains tests for the changed/added code (great if so but not required).
• [ na] I have added a scenario to test my changes.

This PR touches code in the following areas (Check what is applicable):

Frontend

• Shopping cart
• Checkout
• Totals
• [ x] Payment methods

Backend

• Configuration
• Order grid
• Order view
• Invoice view
• Credit memo view
• Shipment view
• Email sending

Order Processing (Mollie communication)

• Creating the order
• Invoicing the order
• Shipping the order
• Refunding (credit memo) the order

Other
If you didn't check any boxes above, please describe your changes in this section.

Please describe the bug/feature/etc this PR contains:

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Scenario to test this code:

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[Frank-Magmodules]

Thanks @evs-xsarus for the PR! We’ll review it with the team, and once it’s approved, we’ll include it in the next release. Appreciate your effort!