Dynamic Dashboard: Preserve existing ordering when refreshing cards.

[hafizrahman]

Closes: #12743

Description

Previously, when refreshing Dashboard when there's a mix of default and new cards, the default cards will always be shown at the top again even if the new cards were set to be displayed at the top previously.

This PR fixes that so the user's cards ordering is preserved.

Testing instructions

1. Start app
2. Edit dashboard, then enable and put an m2 card (e.g: Inbox or Coupons) at the top of the list,
3. Save,
4. On the dashboard, do a pull-to-refresh
5. Ensure that the enabled m2 card on step 2 stays at the top.
6. restart app
7. Ensure that the enabled m2 card on step 2 stays at the top.

[dangermattic]

	1 Warning
⚠️	This PR is assigned to the milestone 18.8. This milestone is due in less than 2 days. Please make sure to get it merged by then or assign it to a milestone with a later deadline.

Generated by 🚫 Danger

[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	pr12811-446709b
	Version	18.7
	Bundle ID	com.automattic.alpha.woocommerce
	Commit	446709b
	App Center Build	WooCommerce - Prototype Builds #9200

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

[itsmeichigo]

Thanks for the quick fix! 💯 This has been bothering me since yesterday!