feat: adding featureFlag for un-deploy

[wrt95]

Description

• Adding featureFlag for undeploy
• Adding basic component

Related Issue(s)

• Set up basic frontend with featureFlag and button to click #14192

Dependencies

• refactor: replace altinn confirm dialog with studio components #14197

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)

[codecov]

Codecov Report

Attention: Patch coverage is 91.66667% with 1 line in your changes missing coverage. Please review.

Project coverage is 95.52%. Comparing base (3eb8149) to head (b63fa57).
Report is 3 commits behind head on main.

Files with missing lines	Patch %	Lines
...es/appPublish/components/DeploymentEnvironment.tsx	66.66%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #14198      +/-   ##
==========================================
- Coverage   95.53%   95.52%   -0.01%     
==========================================
  Files        1824     1826       +2     
  Lines       23745    23757      +12     
  Branches     2751     2752       +1     
==========================================
+ Hits        22684    22695      +11     
  Misses        807      807              
- Partials      254      255       +1     

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[framitdavid]

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