Implementing the order wrapper class in the root files

[wjrosa]

First PR: #4080

Changes proposed in this Pull Request:

This PR is another in a series of implementations of the proposal of #3654. This iteration implements the order wrapper class on our root extension files.

Testing instructions

Code review. Check if the tests are still passing. A slight smoke test on the checkout pages with regular payment methods in the new checkout experience would be nice: enabling them, and trying to make purchases with them.

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

Changelog entry

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Changelog Entry Comment

Comment

Post merge

• Added testing instructions to the Release Testing Instructions wiki page (or does not apply)
• Added the needs docs label (or does not apply)
• Included this PR in the Release Thread scope (or does not apply)

[github-actions]

📈 PHP Unit Code Coverage Report

Package	Line Rate	Health
includes/class-wc-gateway-stripe.php	25%	❌
includes/class-wc-stripe-helper.php	58%	❌
includes/class-wc-stripe-intent-controller.php	25%	❌
includes/class-wc-stripe-order-handler.php	28%	❌
includes/class-wc-stripe-webhook-handler.php	31%	❌
Summary	44% (6972 / 15891)	❌