[WCiOS17] Update .onchange() usage to iOS17 API

[iamgabrielma]

Part of WOOMOB-1003

• Requires bump to iOS17 to be merged first: [WCiOS17] Bump minimum deployment target to iOS17 #16003

Description

This PR addresses ~50 warnings related to the .onChange usage across Order creation and POS, by moving them to use the new iOS17+ API.

The previous API has been updated and deprecated from forcing us to use 1 parameter, to instead:

• Use a zero-parameter closure when we don’t care about the value.
• Use a two-parameter closure (oldValue, newValue) if we need at least one of them.

All changes are a refactor, so no behavior should be changed. Most of times we either don't care about the value and just react to it, or we care about newValue only.

Testing information

Changes affect multiple files, but superficial smoke testing Order Creation and POS flows should be sufficient, ie:

• In the app, create an order, use the product filters, add a coupon, use the stepper to increase/decrease quantity, expand the totals view, process a payment via TTP, send a receipt. Do this via single selection in mobile, and multi-select in tablet.
• In POS, setup scanner, go through payment flow, and send a receipt. At some point also move to split view and reduce POS view until is not eligible to use.

Screenshots

N/A

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• I have considered if this change warrants user-facing release notes and have added them to RELEASE-NOTES.txt if necessary.

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[iamgabrielma]

It doesn't seem we need the capture list here: .onChange(of: fixedContentSize) already re-runs the closure every time fixedContentSize changes, so capturing it when created serves no purpose as it will always have the latest value when the closure runs anyway

[iamgabrielma]

Passing it implicitly as $0 is no longer something we can do, since we're using the new value inside the closure, we need to be declare it explicitly in .onChange before using it.