Setting ebs_volume_count to more than 1 results in terraform error

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## Describe the Bug
When set ebs_volume_count = 2 (more than 1), it will result in terraform error

```
╷
│ Error: Invalid index
│
│ on modules/cp-ec2-group/main.tf line 163, in resource "aws_volume_attachment" "default":
│ 163: instance_id = aws_instance.default.*.id[count.index]
│ ├────────────────
│ │ aws_instance.default is tuple with 1 element
│ │ count.index is 1
│
│ The given key does not identify an element in this collection value: the given index is greater than or equal to the length of the collection.

```
## Expected Behavior
Create and attach two additional ebs volumes

## Steps to Reproduce
for example
```
module "instance" {
source = "./modules/cp-ec2-group"

namespace = "eg"
stage = "prod"
name = "app"
ami = "ami-a4dc46db"
ami_owner = "099720109477"
ssh_key_pair = var.ssh_key_pair
instance_type = var.instance_type
vpc_id = var.vpc_id
security_groups = var.security_groups
subnet = var.subnet
instance_count = 3
ebs_volume_count = 2
}

```

## Environment (please complete the following information):

- OS: Linux, Mint 20.3, 5.4.0-139-generic
- Terraform v1.3.7

## Additional Context
Could be solved by replace string in main.tf, at line 162.
e.g.:
instance_id = element(aws_instance.default.*.id, floor(count.index / max(var.ebs_volume_count, 1)))

p.s.
there is a limitation, changing the number of EBS will lead to reattaching disks to different instances

Start at modules/cp-ec2-group/main.tf line 163 and reproduce the reported error with instance_count = 3 and ebs_volume_count = 2. Trace how count.index maps EBS attachments to aws_instance.default IDs, then verify that the configuration plans successfully and attaches the requested volumes to the intended instances.

Written by the indexing model from the issue text.