Temporarily disabling Store API integration for express checkouts

[wjrosa]

See p6q7sZ-iSH-p2

Changes proposed in this Pull Request:

This PR temporarily reverses the Store API implementation for ECE due to incompatibilities with the Order Status Management extension. It is just a backup solution; it is not yet intended to move forward.

Testing instructions

• Checkout and build this branch on your test environment (fix/disabling-store-api-due-incompatibility-issues)
• Connect your Stripe account
• Enable express payment methods (Google Pay, Apple Pay)
• As a shopper, accessing the store using a public-facing address, try to purchase any product using express methods
• Confirm you can complete it successfully

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• Covered with tests (or have a good reason not to test in description ☝️)
• Tested on mobile (or does not apply)

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• Added testing instructions to the Release Testing Instructions wiki page (or does not apply)
• Added the needs docs label (or does not apply)
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