Errors during tflocal init

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Running `tflocal init`
```
File ~/.pyenv/versions/3.12.6/lib/python3.12/site-packages/botocore/handlers.py:295, in validate_bucket_name(params, **kwargs)
294 bucket = params['Bucket']
--> 295 if not VALID_BUCKET.search(bucket) and not VALID_S3_ARN.search(bucket):
296 error_msg = (
297 f'Invalid bucket name "{bucket}": Bucket name must match '
298 f'the regex "{VALID_BUCKET.pattern}" or be an ARN matching '
299 f'the regex "{VALID_S3_ARN.pattern}"'
300 )

TypeError: expected string or bytes-like object, got 'list'
```

Why?

Well, terraform-local seems to use hcl2 to parse terraform files.

I have a perfectly standard provider.tf file
```hcl
terraform {
required_version = "~> 1.8"
required_providers {
aws = {
source = "hashicorp/aws"
version = "~> 5.91"
}
awscc = {
source = "hashicorp/awscc"
version = "~> 0.14"
}
archive = {
source = "hashicorp/archive"
version = "~> 2.4"
}
}

backend "s3" {
bucket = "ninety-terraform-state"
key = "devops-infra"
region = "us-east-1"
}
}

provider "aws" {
region = "us-east-1"
}

provider "awscc" {
region = "us-east-1"
}
```

When I parse that with hcl2 I get
```
with open('/home/gmauer/code/ninety-infra/devops/provider.tf', 'r') as fp:
foo = hcl2.load(fp)

In [25]: ...: ...:
In [26]: foo
Out[26]:
{'terraform': [{'required_version': ['~> 1.8'],
'required_providers': [{'aws': [{'source': 'hashicorp/aws',
'version': '~> 5.91'}],
'awscc': [{'source': 'hashicorp/awscc', 'version': '~> 0.14'}],
'archive': [{'source': 'hashicorp/archive', 'version': '~> 2.4'}]}],
'backend': [{'s3': {'bucket': ['ninety-terraform-state'],
'key': ['devops-infra'],
'region': ['us-east-1']}}],
'__start_line__': 1,
'__end_line__': 23}],
'provider': [{'aws': {'region': ['us-east-1'],
'__start_line__': 25,
'__end_line__': 27}},
{'awscc': {'region': ['us-east-1'],
'__start_line__': 29,
'__end_line__': 31}}]}
```
see that `backend[0].s3.bucket`? It's a list! The type signature of the handling code is pretty clear that it expects an `str`

Start at the tflocal init path that reads the Terraform backend configuration and passes the bucket value to botocore, then inspect how hcl2's parsed lists are handled. Reproduce the reported provider.tf case; done means init accepts the scalar backend settings without passing a list as the bucket name.

Written by the indexing model from the issue text.