[WOOMOB-445] UI glitches

[AdamGrzybkowski]

Closes WOOMOB-445

Description

When testing 22.2 two UI glitches were found:

Loading Spinner cut off when opening shipping class

Fix by replacing the bottom margin with a vertical margin to keep it symetrical.

Before	After

Wrong skeletons color in the Plugins screen

The custom composable used a fixed color there. After looking around, I noticed there's a SkeletonView for such a scenario, so I replaced the custom one with it completely. This should ensure the shimmer effect is consistent across the screens.

Before	After

Steps to reproduce / Testing information

Loading Spinner cut off when opening shipping class

1. Make sure you have no shipping classes (this loading is shown only when the list is empty, otherwise cached values are used)
2. Go to product
3. Tap "Shipping" or if it's not there tap "Add more details"
4. Tap "Shipping class"
5. Observe the progress indicator

Wrong skeletons color in the Plugins screen

1. Enable dark theme
2. Go to "Settings"
3. Tap "Installed plugins"
4. Notice the shimmer effect color
5. Switch theme and re-enter the screen to verify the shimmer again

The tests that have been performed

The above

• I have considered if this change warrants release notes and have added them to RELEASE-NOTES.txt if necessary. Use the "[Internal]" label for non-user-facing changes.

[Copilot]

Pull Request Overview

This PR fixes two UI glitches found during testing: a loading spinner being cut off in the shipping class screen and incorrect skeleton colors in the plugins screen. The changes improve visual consistency and proper display of loading states.

• Fixed loading spinner positioning by replacing bottom margin with vertical margin
• Replaced custom shimmer implementation with standard SkeletonView component for consistent theming
• Removed unnecessary animation and brush code from plugins screen

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
fragment_product_shipping_class_list.xml	Updated progress bar margin to fix cut-off issue
PluginsScreen.kt	Replaced custom shimmer implementation with SkeletonView component

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[wpmobilebot]

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

	App Name	WooCommerce-Wear Android
	Platform	⌚️ Wear OS
	Flavor	Jalapeno
	Build Type	Debug
	Commit	26e4676
	Direct Download	woocommerce-wear-prototype-build-pr14609-26e4676.apk

[wpmobilebot]

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

	App Name	WooCommerce Android
	Platform	📱 Mobile
	Flavor	Jalapeno
	Build Type	Debug
	Commit	26e4676
	Direct Download	woocommerce-prototype-build-pr14609-26e4676.apk

[hichamboushaba]

Nice work @AdamGrzybkowski