feat: Remove featureflag multiple data models per task

[lassopicasso]

Description

This PR removes the feature flag: 'multipleDataModelsPerTask and the code related to this + updates tests.

What should be tested before merging this to main

Pre-Test Setup

1. Navigate to the Datamodell page
2. Create and generate several data models with distinct data model fields
3. Navigate to the Prosesser page
4. Create a new layoutset and bind it to a data model so it has a default data model

Test cases

1. Default data model binding for layout set
   a. Create a new layout set i prosesser
   b. Bind the layout set to a default data model
   c. Go to “Utforming” section and add a component
   d. Verify that the default data model is selected in the data model bindings for the component.

2. Select an Alternative Data Model in Data Model Bindings
   a. Confirm that you can select a data model other than the default in the data model bindings for a component.

3. Switch between data models in data model bindings
   a. Test switching between different data models in the data model bindings for a component
   b. Ensure the related data model fields are displayed correctly in the dropdown list for each selection.

4. Preview Functionality with non-default data models
   a. Verify that the preview functionality works as expected when a data model other than the default is selected.
   b. See releated issue: Preview Fails When Linking Component to Non-Default Data Model #14104

5. Layout configuration – correct bindings displayed
   a. In the layout configuration in “se siste endringer”:
   i. Check that the correct bindings are displayed when selecting data model fields for the default data model
   ii. Check that the correct bindings are displayed when selecting a non-default data model and one of its data model fields

Related Issue(s)

• Remove featureflag for multiple data models #13797

Verification

• Your code builds clean without any errors or warnings
• Manual testing done (required)
• Relevant automated test added (if you find this hard, leave it and we'll help out)

Documentation

• User documentation is updated with a separate linked PR in altinn-studio-docs. (if applicable)

[lassopicasso]

This may need to be set to blocked after review until this is solved #14104, to make sure that number 4 works,Preview Functionality with non-default data models.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 95.52%. Comparing base (37d92b5) to head (417f66a).
Report is 2 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #14171      +/-   ##
==========================================
- Coverage   95.52%   95.52%   -0.01%     
==========================================
  Files        1826     1826              
  Lines       23757    23753       -4     
  Branches     2752     2750       -2     
==========================================
- Hits        22695    22691       -4     
  Misses        807      807              
  Partials      255      255              

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[mlqn]

Nice work! 🚀 I just left suggestions to remove some console.log.

[lassopicasso]

Nice work! 🚀 I just left suggestions to remove some console.log.

Thx! :)