[Shipping Labels] Split shipments instructions notice

[selanthiraiyan]

Closes: #15305

Description

Starts showing the instructions notice in the split shipments flow.

Changes

• Alter Notice to work without a title.
• Use BoldableTextView in Notice for showing markdown message.
• Show instructions notice if there is no selection made in split shipments screen.
• Shows "Split shipments" view only if a shipping label has not been purchased.

Steps to reproduce

1. Log in to a test store with the Woo Shipping plugin set up.
2. Create an order with multiple products and different quantities for each product.
3. Enter a valid shipping address for the order.
4. Open the order detail page.
5. Tap "Create shipping label".
6. Tap "Split shipments".
7. Validate that you see a notice with instructions to select items to split into shipments. Design - bsLNrhmi2xQZB4C0TzjmHB-fi-942_42236
8. Selecting any item should make that instructions notice disappear.

Testing information

Tested that the instructions notices is displayed as described above.

Screenshots

Purchased a shipping label

Before	After

Notice for instructions

Simulator.Screen.Recording.-.iPhone.16.Pro.-.2025-03-24.at.14.49.42.mp4

---

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

Reviewer (or Author, in the case of optional code reviews):

Please make sure these conditions are met before approving the PR, or request changes if the PR needs improvement:

• The PR is small and has a clear, single focus, or a valid explanation is provided in the description. If needed, please request to split it into smaller PRs.
• Ensure Adequate Unit Test Coverage: The changes are reasonably covered by unit tests or an explanation is provided in the PR description.
• Manual Testing: The author listed all the tests they ran, including smoke tests when needed (e.g., for refactorings). The reviewer confirmed that the PR works as expected on all devices (phone/tablet) and no regressions are added.

[wpmobilebot]

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

	App Name	WooCommerce iOS
	Build Number	pr15406-44b4cea
	Version	22.0
	Bundle ID	com.automattic.alpha.woocommerce
	Commit	44b4cea
	App Center Build	WooCommerce - Prototype Builds #13392

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

[itsmeichigo]

LGTM