Issue/12742 check objective is set from preview

[JorgeMucientes]

Closes: #12742

Description

This PR adds a couple things:

• Check that the campaign objective is set before the user can move on in the creation flow
• Adds a feature flag for Objective section
• Unit tests for the new objective check.

Testing information

1. Trigger Blaze campaign creation flow
2. Without setting and objective tap on Confirm details
3. Notice a dialog is shown requesting to add an objective
4. Tap on Select objective from the dialog
5. Notice how app navigates to objective screen (currently empty)

The tests that have been performed

The above

Images/gif

dmeoObjectiveCheck.mp4

• 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	f9c4914
	Direct Download	woocommerce-wear-prototype-build-pr12743-f9c4914.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	f9c4914
	Direct Download	woocommerce-prototype-build-pr12743-f9c4914.apk

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 90.00000% with 3 lines in your changes missing coverage. Please review.

Project coverage is 40.70%. Comparing base (14b24c0) to head (f9c4914).

Files with missing lines	Patch %	Lines
...n/preview/BlazeCampaignCreationPreviewViewModel.kt	88.88%	1 Missing and 2 partials ⚠️

Additional details and impacted files

@@            Coverage Diff            @@
##              trunk   #12743   +/-   ##
=========================================
  Coverage     40.69%   40.70%           
- Complexity     5730     5735    +5     
=========================================
  Files          1232     1232           
  Lines         69445    69455   +10     
  Branches       9630     9631    +1     
=========================================
+ Hits          28260    28271   +11     
+ Misses        38577    38576    -1     
  Partials       2608     2608           

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