[WOOMOB-1829] Fix loading indicator colors to match Figma design

[kidinov]

Closes WOOMOB-1829

Description

Fixed loading indicator colors to match Figma design by creating two separate composables:

1. WooPosCircularLoadingIndicator - Big spinner for splash/loading screens with purple arc on light purple background
2. WooPosButtonLoadingIndicator - Small spinner for buttons with white arc on light purple background

Previously, WooPosButtons was passing incorrect colors to the loading indicator. Now each variant has hardcoded colors to prevent misuse.

Also renamed the file from WooPosCircularLoadingIndicator.kt to WooPosLoadingIndicators.kt.

Test Steps

1. Open any screen with a loading spinner (splash screen, totals screen preparing reader)
2. Verify the spinner shows purple arc on light purple background
3. Trigger a button loading state (e.g., checkout flow)
4. Verify the button spinner shows white arc on light purple background

Images/gif

• 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.

[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	4e4cdb7
	Direct Download	woocommerce-wear-prototype-build-pr15043-4e4cdb7.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	4e4cdb7
	Direct Download	woocommerce-prototype-build-pr15043-4e4cdb7.apk

[codecov-commenter]

Codecov Report

❌ Patch coverage is 0% with 24 lines in your changes missing coverage. Please review.
✅ Project coverage is 38.60%. Comparing base (eda322f) to head (4e4cdb7).

Files with missing lines	Patch %	Lines
...mon/composeui/component/WooPosLoadingIndicators.kt	0.00%	23 Missing ⚠️
...woopos/common/composeui/component/WooPosButtons.kt	0.00%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##              trunk   #15043      +/-   ##
============================================
- Coverage     38.61%   38.60%   -0.01%     
  Complexity    10311    10311              
============================================
  Files          2163     2163              
  Lines        122674   122687      +13     
  Branches      16934    16940       +6     
============================================
  Hits          47365    47365              
- Misses        70503    70516      +13     
  Partials       4806     4806              

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