[Bulk Update Orders] Unit tests

[hafizrahman]

Part of: #13112

Description

This PR adds unit tests related to the bulk update order functionalities in the view model.

Steps to reproduce

Just ensure unit tests pass.

Testing information

n/a

The tests that have been performed

n/a

Images/gif

n/a

• 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.

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 big (tablet) and small (phone) in case of UI changes, and no regressions are added.

[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	ee03135
	Direct Download	woocommerce-wear-prototype-build-pr13232-ee03135.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	ee03135
	Direct Download	woocommerce-prototype-build-pr13232-ee03135.apk

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 40.66%. Comparing base (4bb5368) to head (ee03135).
Report is 1 commits behind head on trunk.

Additional details and impacted files

@@             Coverage Diff              @@
##              trunk   #13232      +/-   ##
============================================
+ Coverage     40.61%   40.66%   +0.04%     
- Complexity     6386     6396      +10     
============================================
  Files          1351     1351              
  Lines         77506    77506              
  Branches      10661    10661              
============================================
+ Hits          31480    31514      +34     
+ Misses        43246    43208      -38     
- Partials       2780     2784       +4     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.