feat: add PayPal to Checkout Components native-UI payments (ORC-6513)

[OnurVar]

Summary

PayPal flows through the generic usePrimerPaymentMethod('PAYPAL') — no bespoke usePayPal hook. Third step of the APM hook unification (after Google Pay #376, Apple Pay #374).

Because PayPal is a both-platform NATIVE_UI method with plain list-membership availability, it needs zero method-specific code — the foundation's generic hook + startNativeUI already drive it. So this PR is the unification paying off: the bespoke usePayPal is removed and PayPal rides the same path as every other native-UI method. The diff is just the test coverage proving it.

• usePrimerPaymentMethod('PAYPAL') → kind: 'nativeUi'; start() → startNativeUI('PAYPAL') → the native Headless SDK opens the PayPal approval browser; outcome arrives on the shared paymentOutcome.
• Available on both iOS and Android whenever PayPal is in the session — no platform guard (unlike Google/Apple Pay).
• Renders as a standard method row (no dedicated native button).

Breaking change

usePayPal and the PayPalController / PayPalAvailabilityError types are removed — use usePrimerPaymentMethod('PAYPAL') and narrow on kind: 'nativeUi'.

Base

ov/feat/ACC-6923-apple-pay-component (#374).

Jira

ORC-6513

Test plan

• yarn typecheck / yarn lint — clean
• yarn jest — green; new usePrimerPaymentMethod PayPal cases (routes to nativeUi; available on both platforms when listed; start() configures/shows PAYPAL)
• Manual Android — PayPal → approval browser → onCheckoutComplete (sandbox payment succeeded)
• Manual iOS — PayPal → approval browser → onCheckoutComplete (sandbox payment succeeded)

[github-actions]

	Warnings
⚠️	This PR doesn't seem to contain any updated Unit Test for Swift 🤔. Please consider double checking it 🙏

	Messages
📖	✅ No SwiftLint violations found.

Generated by 🚫 Danger Swift against bad5150

[github-actions]

	Fails
🚫	🙁 Found 1 ESLint violations.
🚫	src/Components/hooks/useCardNetworkDescriptor.ts#L18 - ** ESLint **: Promises must be awaited, end with a call to .catch, end with a call to .then with a rejection handler or be explicitly marked as ignored with the void operator. - (@typescript-eslint/no-floating-promises)

	Warnings
⚠️	Please assign someone aside from CODEOWNERS (@checkout-pci-reviewers) to review this PR.

Generated by 🚫 dangerJS against bad5150

[unblocked]

✅ No issues found

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[github-actions]

	Warnings
⚠️	This PR doesn't seem to contain any updated Unit Test for Kotlin 🤔. Please consider double checking it 🙏

	Messages
📖	✅ No detekt violations found.

Generated by 🚫 Danger Kotlin against bad5150

[OnurVar]

Superseded by the consolidated APM-unification stack — #392 (native-UI) → #393 (bank) → #394 (raw-data) → #395 (QR) → #396 (Klarna). Closing in favor of those; the new stack carries the same work plus the review fixes.