Shipping Labels: Display base rate on service card

[itsmeichigo]

Closes WOOMOB-861

Description

This PR updates the rates displayed on the selected shipping service to be the base rate to align with the web and Android.

Testing steps

1. Log in to a test store with Woo Shipping extension.
2. Navigate to the Orders tab and select an order eligible for creating shipping labels.
3. Select Create shipping label > select a package > select a shipping service.
4. Confirm that the service card displays the base rate, not the total rate. The rate should stay unchanged when selecting any additional services.

Testing information

Tested on simulator iPhone 16 iOS 18.4

Screenshots

Simulator.Screen.Recording.-.iPhone.16.-.2025-07-16.at.14.32.37.mp4

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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.

[wpmobilebot]

📲 You can test the changes from this Pull Request in WooCommerce iOS Prototype by scanning the QR code below to install the corresponding build.

	App Name	WooCommerce iOS Prototype
	Build Number	pr15916-e064558
	Version	22.8
	Bundle ID	com.automattic.alpha.woocommerce
	Commit	e064558
	Installation URL	3a72e8a38ljho

Automatticians: You can use our internal self-serve MC tool to give yourself access to those builds if needed.

[RafaelKayumov]

LGTM