### Is there an existing issue for this?

- [X] I have searched the existing issues

### Current Behavior

I'm using [Localstack with the Rust SDK](https://docs.aws.amazon.com/sdk-for-rust/latest/dg/localstack.html), and it is reporting an error parsing the `RunInstancesResponse` type:

```
Error: Error parsing XML: expected (boolean: `com.amazonaws.ec2#Boolean`)

Caused by:
    0: Error parsing XML: expected (boolean: `com.amazonaws.ec2#Boolean`)
    1: Error parsing XML: expected (boolean: `com.amazonaws.ec2#Boolean`)
```

The response contains this:

```
<ebsOptimized>False</ebsOptimized>
```

which does not conform to the API reference's description of [AttributeBooleanValue](https://docs.aws.amazon.com/AWSEC2/latest/APIReference/API_AttributeBooleanValue.html), which says that the valid values are `true` or `false`.

### Expected Behavior

The API should return boolean values in lowercase as specified by the Amazon API Reference.

### How are you starting LocalStack?

With a docker-compose file

### Steps To Reproduce

#### How are you starting localstack (e.g., `bin/localstack` command, arguments, or `docker-compose.yml`)

```yaml
version: "3.8"

services:
  localstack:
    container_name: "${LOCALSTACK_DOCKER_NAME-localstack_main}"
    image: localstack/localstack
    network_mode: bridge
    ports:
      - "127.0.0.1:4510-4559:4510-4559"  # external service port range
      - "127.0.0.1:4566:4566"            # LocalStack Edge Proxy
    environment:
      - DEBUG=${DEBUG-}
      - DATA_DIR=${DATA_DIR-}
      - LAMBDA_EXECUTOR=${LAMBDA_EXECUTOR-}
      - DOCKER_HOST=unix:///var/run/docker.sock
    volumes:
      - "${LOCALSTACK_VOLUME_DIR:-./volume}:/var/lib/localstack"
      - "${DOCKER_SOCK:-/var/run/docker.sock}:/var/run/docker.sock"
```

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

```rust
let ec2: aws_sdk_ec2::Client = ...;
let resp = ec2
    .run_instances()
    .image_id(image_id)
    .max_count(1)
    .min_count(1)
    .key_name(key_name)
    .security_group_ids(gid)
    .subnet_id(sid)
    .send()
    .await?;
```


### Environment

```markdown
- OS: Ubuntu 18.04 LTS
- LocalStack:

localstack_main | LocalStack version: 1.0.2.dev
localstack_main | LocalStack Docker container id: 73a491727a3c
localstack_main | LocalStack build date: 2022-07-20
localstack_main | LocalStack build git hash: e105e488
```
```


### Anything else?

_No response_
import binascii
import datetime
import json
import re
import xml.etree.ElementTree as ET
from binascii import crc32
from struct import pack
from typing import Dict, Optional, Union
from urllib.parse import parse_qs
import xmltodict
from flask import Response as FlaskResponse
from moto.core.exceptions import JsonRESTError
from requests.models import CaseInsensitiveDict
from requests.models import Response as RequestsResponse
from localstack.aws.accounts import get_aws_account_id
from localstack.config import DEFAULT_ENCODING
from localstack.constants import APPLICATION_JSON, HEADER_CONTENT_TYPE
from localstack.utils.aws import aws_stack
from localstack.utils.http import replace_response_content
from localstack.utils.json import json_safe
from localstack.utils.strings import (
    short_uid,
    str_startswith_ignore_case,
    to_bytes,
    to_str,
    truncate,
)
REGEX_FLAGS = re.MULTILINE | re.DOTALL
class ErrorResponse(Exception):