[terraform-ibm-landing-zone-vpc] classic_access arg has been deprecated from `ibm_is_vpc`

[ocofaigh]

Starting to see warning like this:

TestRunStandardExample 2024-11-11T12:17:34Z logger.go:66: │ Warning: Argument is deprecated
TestRunStandardExample 2024-11-11T12:17:34Z logger.go:66: │ 
TestRunStandardExample 2024-11-11T12:17:34Z logger.go:66: │   with module.pag_all_inclusive.module.vpc.ibm_is_vpc.vpc,
TestRunStandardExample 2024-11-11T12:17:34Z logger.go:66: │   on .terraform/modules/pag_all_inclusive.vpc/main.tf line 31, in resource "ibm_is_vpc" "vpc":
TestRunStandardExample 2024-11-11T12:17:34Z logger.go:66: │   31:   classic_access              = var.classic_access
TestRunStandardExample 2024-11-11T12:17:34Z logger.go:66: │ 
TestRunStandardExample 2024-11-11T12:17:34Z logger.go:66: │ Classic access is deprecated
```

[ocofaigh]

Should be removed from terraform-ibm-landing-zone too