fix(zero_trust_access_group): traversal of hcl

[vaishakdinesh]

Step 1: v4 terraform apply
    Status: ✓ SUCCESS

  Step 2: Migration (v4 → v5)
    Status: ✓ SUCCESS

  Step 3: v5 plan (before apply)
    Status: ✓ SUCCESS - Drift matched exemptions
    Result: 69 material changes (69 matched exemptions, 0 unmatched)
    Terraform: Plan: 16 to import, 8 to add, 63 to change, 0 to destroy.

  Step 4: v5 terraform apply
    Status: ✓ SUCCESS

  Step 5: v5 plan (after apply)
    Status: ✓ SUCCESS - Stable state achieved
    Result: 11 material changes matched exemptions (0 unmatched)