[Custom Fields] Some fixes

[hichamboushaba]

Description

This PR fixes some issues with the Custom Fields feature:

1. The custom field content wasn't capturing click events (this was raised here and here), this was fixed in
   948e8ee
2. The condition I was using to decide when to check for duplicate fields wasn't reliable, when editing a new non-saved field, we were ignoring the check, this was fixed in ad94ecd
3. We had a corner case that when editing a new non-saved field, we would add a new entry instead of updating the existing one, this was fixed in 205a684 and
   0c8557f

Steps to reproduce

1. Make sure an order has at least one custom field.
2. Opent the order in the app.
3. Tap on View Custom Fields.

Testing information

TC1:

• Make sure tapping on the custom field's content opens the editor.

TC2:

1. Add a new field.
2. Tap on Done.
3. Tap on the new field to edit it again.
4. Update the key to match the content of an existing one.
5. Tap on Done.
6. Confirm an error is shown.

TC3:

1. Add a new field.
2. Tap on Done.
3. Tap on the new field to edit again.
4. Make some changes.
5. Tap on Done.
6. Confirm the field was updated correctly.

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.

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.

[dangermattic]

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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	7de6ad0
	Direct Download	woocommerce-wear-prototype-build-pr12582-7de6ad0.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	7de6ad0
	Direct Download	woocommerce-prototype-build-pr12582-7de6ad0.apk

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 94.11765% with 1 line in your changes missing coverage. Please review.

Project coverage is 40.65%. Comparing base (4be88f0) to head (7de6ad0).

Files with missing lines	Patch %	Lines
...customfields/editor/CustomFieldsEditorViewModel.kt	92.85%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@                     Coverage Diff                      @@
##             issue/12578-copy-field   #12582      +/-   ##
============================================================
+ Coverage                     40.64%   40.65%   +0.01%     
- Complexity                     5670     5671       +1     
============================================================
  Files                          1228     1228              
  Lines                         68938    68947       +9     
  Branches                       9547     9550       +3     
============================================================
+ Hits                          28019    28032      +13     
+ Misses                        38345    38343       -2     
+ Partials                       2574     2572       -2     

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[JorgeMucientes]

Good job @hichamboushaba 👍🏼
While all the test worked as expected I did notice an scenario that it is not handled. It is is possible to add multiple new custom fields with the same key value. It is not until I click save that duplicates are handled. However, the resulting behavior is a bit weird from a users perspective. I think we should avoid being able to add new custom fields with the same key, just as you added a check to avoid editing an existing key to have the same value of other custom fields.

allowsToAddDuplicatesAndThenMerges.mp4

Feel free to address this change in a different PR. Won't block this one for it.

[hichamboushaba]

It is is possible to add multiple new custom fields with the same key value. It is not until I click save that duplicates are handled. However, the resulting behavior is a bit weird from a users perspective.

Great find @JorgeMucientes, I'll address this later, and I'll share it with the iOS team, as for now we are checking against the saved items, and we don't check against the items that are not saved yet.