feat: Validate create subform in nextrecommendedaction

[lassopicasso]

Description

• This PR introduces validation for creating a new subform within the recommended next action container for the subform component in the main layout set.

Video of this PR

Receives an error after creating, this is also in main, new issue here: #13967

validationcreatesubform.mp4

• Additionally, I have implemented a reusable hook, useCreateSubform, to facilitate subform creation. This hook includes specific parameters, such as the "subform" string, and is used in a couple of places.

Related Issue(s)

• add validation for creating a new subform input in StudioCard/ nextRecommendAction #13931

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)

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 95.21%. Comparing base (5a3082b) to head (0649363).
Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main   #13966   +/-   ##
=======================================
  Coverage   95.20%   95.21%           
=======================================
  Files        1701     1702    +1     
  Lines       22519    22525    +6     
  Branches     2638     2638           
=======================================
+ Hits        21440    21447    +7     
+ Misses        833      832    -1     
  Partials      246      246           

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

[JamalAlabdullah]

It works nice👍

[JamalAlabdullah]

Nice jobb 🚀

[Jondyr]

Works well 👍 ✅