AWS::EC2::VPC - Missing proper defaults for optional parameters in Cloud Control definition

### Name of the resource

AWS::EC2::VPC

### Resource Name

_No response_

### Issue Description

using `awscc` terraform provider without specifying optional parameters yields in changes due to missing default values for

- `enable_dns_hostnames`
- `enable_dns_support`
- `instance_tenancy`

1. create a vpc using the definition below
2. perform a 2nd terraform apply - here you'll see the default values attempt to change and fail

### Terraform awscc provider
```hcl
resource "awscc_ec2_vpc" "test" {
cidr_block = "10.0.0.0/16"
tags = [{
key = "test"
value = "test"
},
{
key = "test2"
value = "test2"
}
]
}
```

### 2nd `terraform apply` attempts to change optional parameter values to null

```
# awscc_ec2_vpc.test will be updated in-place
~ resource "awscc_ec2_vpc" "test" {
- enable_dns_hostnames = false -> null
- enable_dns_support = true -> null
id = "vpc-0e070ec0bd051d661"
- instance_tenancy = "default" -> null
~ tags = [
+ {
+ key = "test2"
+ value = "test2"
},
# (1 unchanged element hidden)
]
# (6 unchanged attributes hidden)
}
```

### Expected Behavior

optional values should yield no change when not specified

### Observed Behavior

a change is seen because default values are not properly set in resource object definition

### Test Cases

see above

### Other Details

_No response_