### Is there an existing issue for this?

- [X] I have searched the existing issues

### Current Behavior

DynamoDB does not correctly namespace resources based on region and account ID. 

For instance, using the same table name across accounts and regions throws an error.

### Expected Behavior

It must be possible to create resources with same name on different regions and/or different accounts.

### How are you starting LocalStack?

With a docker-compose file

### Steps To Reproduce

#### Client commands (e.g., AWS SDK code snippet, or sequence of "awslocal" commands)

```
  $ AWS_ACCESS_KEY_ID=445500880268 AWS_DEFAULT_REGION=eu-central-1 \
    awslocal dynamodb create-table --table-name CertificateTargets-local1 \
        --key-schema AttributeName=target_uuid,KeyType=HASH \
        --attribute-definitions AttributeName=target_uuid,AttributeType=S \
        --provisioned-throughput ReadCapacityUnits=1000,WriteCapacityUnits=1000

  $ AWS_ACCESS_KEY_ID=445500880268 AWS_DEFAULT_REGION=us-east-1 \
    awslocal dynamodb create-table --table-name CertificateTargets-local1 \
        --key-schema AttributeName=target_uuid,KeyType=HASH \
        --attribute-definitions AttributeName=target_uuid,AttributeType=S \
        --provisioned-throughput ReadCapacityUnits=1000,WriteCapacityUnits=1000

    # ResourceInUseException!

  $ AWS_ACCESS_KEY_ID=000000000000 \
    awslocal dynamodb create-table --table-name CertificateTargets-local1 \
        --key-schema AttributeName=target_uuid,KeyType=HASH \
        --attribute-definitions AttributeName=target_uuid,AttributeType=S \
        --provisioned-throughput ReadCapacityUnits=1000,WriteCapacityUnits=1000

    # ResourceInUseException!
```

### Environment

```markdown
OS: Ubuntu 22.04
LocalStack: latest
```


### Anything else?

_No response_
key = f"{aws_stack.get_region()}/{table_name}"
        schema = SCHEMA_CACHE.get(key)
        if not schema:
            
            ddb_client = aws_stack.connect_to_service("dynamodb")
            try:
                schema = ddb_client.describe_table(TableName=table_name)
                SCHEMA_CACHE[key] = schema
            except Exception as e:
                if "ResourceNotFoundException" in str(e):
                    raise ResourceNotFoundException(f"Unknown table: {table_name}") from e
                raise
        return schema
class ItemFinder:
    @staticmethod
    def find_existing_item(put_item: Dict, table_name=None) -> Optional[Dict]:
        from localstack.services.dynamodb.provider import ValidationException
        table_name = table_name or put_item["TableName"]
        ddb_client = aws_stack.connect_to_service("dynamodb")
        search_key = {}
        if "Key" in put_item:
            search_key = put_item["Key"]
        else:
            schema = SchemaExtractor.get_table_schema(table_name)
            schemas = [schema["Table"]["KeySchema"]]
            for index in schema["Table"].get("GlobalSecondaryIndexes", []):
                
                
                pass