fix: standardize variable names in postBuild substitution

[avnes]

Describe your changes

This pull request makes a minor update to the variable names used in the Helm chart dependencies specification for 1Password Connect. The change improves naming consistency by updating the variable prefixes to match the rest of the codebase.

• Updated variable names from fluxcd_aws_region and fluxcd_aws_workload_account_id to flux_aws_region and flux_workload_account_id in _sub/security/helm-1password-connect/dependencies.tf for consistency.

Checklist before requesting a review

• I have tested changes in my sandbox
• I have added the needed changes in the test/integration folder to apply my changes in QA. Read the guide on adding environment variables in QA
• I have rebased the code to master (or merged in the latest from master)

Is it a new release?

• Apply a release tag release:(major|minor|patch), following semantic versioning in this guide or norelease if there is no changes to the Terraform code