### Is there an existing issue for this?

- [X] I have searched the existing issues

### Current Behavior

Localstack (1.0.2) returns what appears to be an incorrect error response when calling `get-object` against a non-existent bucket:

```
$ awslocal --debug s3api get-object --bucket=not-exists-2341234 --key=doesnt-matter.txt doesnt-matter.txt 2>&1 | grep Error | uniq
b"<?xml version='1.0' encoding='utf-8'?>\n<ErrorResponse><Error><Code>NoSuchBucket</Code><Message>The specified bucket does not exist</Message><Type>Sender</Type></Error><RequestId>3FA3WN14HJTCNKT0TFF6LIKTAUQ0XO3AB7MUCIQAIW8KST6T0BA1</RequestId></ErrorResponse>"
```

```
$ aws --debug s3api get-object --bucket=not-exists-2341234 --key=doesnt-matter.txt doesnt-matter.txt 2>&1 | grep Error | uniq
b'<?xml version="1.0" encoding="UTF-8"?>\n<Error><Code>NoSuchBucket</Code><Message>The specified bucket does not exist</Message><BucketName>not-exists-2341234</BucketName><RequestId>99NA328HYHDQH2VN</RequestId><HostId>Kp5IOfCoHrw8Hvo8VL+f994yByXJGECQ4Fy5eNoY/7MPpMcHz2QygoG23ILrmF1TkiYoR+k2Njg=</HostId></Error>'
```
Pretty-printing the XML makes the difference in behaviour clearer:

```xml
<ErrorResponse>
    <Error>
        <Code>NoSuchBucket</Code>
        <Message>The specified bucket does not exist</Message>
        <Type>Sender</Type>
    </Error>. 
    <RequestId>3FA3WN14HJTCNKT0TFF6LIKTAUQ0XO3AB7MUCIQAIW8KST6T0BA1</RequestId>
</ErrorResponse>
```

vs

```xml
<Error>
    <Code>NoSuchBucket</Code>
    <Message>The specified bucket does not exist</Message>
    <BucketName>not-exists-2341234</BucketName>
    <RequestId>99NA328HYHDQH2VN</RequestId>. 
    <HostId>Kp5IOfCoHrw8Hvo8VL+f994yByXJGECQ4Fy5eNoY/7MPpMcHz2QygoG23ILrmF1TkiYoR+k2Njg=</HostId>
</Error>
```

I've also observed the same behaviour when calling the `get-object` API from the Rust SDK.

The problem does not appear prior to version `1.0.0`.

### Expected Behavior

The returned error should have the format described in the spec:

https://docs.aws.amazon.com/AmazonS3/latest/API/ErrorResponses.html

### 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`)

    docker run -p 4566:4566 localstack/localstack:1.0.2

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

    awslocal --debug s3api get-object --bucket=not-exists-2341234 --key=doesnt-matter.txt doesnt-matter.txt 2>&1 | grep Error | uniq


### Environment

```markdown
- OS: OSX
- LocalStack: 1.0.2
```


### Anything else?

The same behaviour is observed on `1.0.0`. Reverting to `0.14.5` we see:

```xml
<Error>
    <Code>NoSuchBucket</Code>
    <Message>The specified bucket does not exist</Message>
    <BucketName></BucketName>
    <RequestID>7a62c49f-347e-4fc4-9331-6e8eEXAMPLE</RequestID>
</Error>
```

which is the correct behaviour.
(a language to define services in a - somewhat - protocol-agnostic
way). The "peculiarities" in this serializer code usually correspond
to certain so-called "traits" in Smithy.
The result of the serialization methods is the HTTP response which can
be sent back to the calling client.
**Experimental:** The serializers in this module are still experimental.
When implementing services with these serializers, some edge cases might
not work out-of-the-box.
"""
import abc
import base64
import functools
import json
import logging
from abc import ABC
from binascii import crc32
from datetime import datetime
from email.utils import formatdate
from struct import pack
from typing import Any, Iterable, Iterator, Optional, Tuple, Union
from xml.etree import ElementTree as ETree
from boto.utils import ISO8601
from botocore.model import ListShape, MapShape, OperationModel, ServiceModel, Shape, StructureShape
from botocore.serialize import ISO8601_MICRO
from botocore.utils import calculate_md5, is_json_value_header, parse_to_aware_datetime
from moto.core.utils import gen_amzn_requestid_long
from localstack.aws.api import HttpResponse, ServiceException
from localstack.utils.common import to_bytes, to_str
LOG = logging.getLogger(__name__)
class ResponseSerializerError(Exception):