test: adds new tests for new variable service

[italojohnny]

adds two new tests for the new delete_variable_by_id method to improve test coverage

[github-actions]

Pull Request Validation Report

This comment is automatically generated by Conventional PR

Whitelist Report

Whitelist	Active	Result
Pull request is a draft and should be ignored	✅	❌
Pull request is made by a whitelisted user and should be ignored	❌	❌
Pull request is submitted by a bot and should be ignored	✅	❌
Pull request is submitted by administrators and should be ignored	❌	❌

Result

Pull request does not satisfy any enabled whitelist criteria. Pull request will be validated.

Validation Report

Validation	Active	Result
All commits in this pull request has valid messages	❌	✅
Pull request does not introduce too many changes	❌	✅
Pull request has a valid title	✅	✅
Pull request has mentioned issues	❌	✅
Pull request has valid branch name	❌	✅
Pull request should have a non-empty body	✅	✅

Result

Pull request satisfies all enabled pull request rules.

_{Last Modified at 13 Aug 24 13:53 UTC}

[aws-amplify-sa-east-1]

This pull request is automatically being deployed by Amplify Hosting (learn more).

Access this pull request here: https://pr-3306.dmtpw4p5recq1.amplifyapp.com