The unmeaning Region parameter became mandatory for MRAP endpoint

### Describe the bug

After an upgrade from 1.9.157 to 1.11.4, the parameter Region became mandatory when trying to connect to a MRAP accesspoint.

As described in documentation https://docs.aws.amazon.com/AmazonS3/latest/userguide/MultiRegionAccessPointRequests.html

> Multi-Region Access Point ARNs don't include an AWS Region

The region should not be mandatory when using MRAP accesspoints.
It should either be ignored or a warning should be raised/logged.

### Expected Behavior

The S3 requests are successful without the need to set a region ; the same as it was with SDK 1.9.157.

### Current Behavior

Below are the traces that are logged when we create the S3Client() class and create the HeadObject request.
```
[DEBUG] 2023-04-24 13:49:14.401 ClientConfiguration [140256500507328] Request Compression enabled
[DEBUG] 2023-04-24 13:49:14.401 ClientConfiguration [140256500507328] ClientConfiguration will use MinReqCompression: 10240
[DEBUG] 2023-04-24 13:49:14.401 ClientConfiguration [140256500507328] ClientConfiguration will use SDK Auto Resolved profile: [default] if not specified by users.
[WARN] 2023-04-24 13:49:14.401 ClientConfiguration [140256500507328] Retry Strategy will use the default max attempts.
[INFO] 2023-04-24 13:49:14.401 CurlHandleContainer [140256500507328] Initializing CurlHandleContainer with size 25
[TRACE] 2023-04-24 13:49:14.403 Aws::Endpoint::DefaultEndpointProvider [140256378881600] Endpoint bool eval parameter: UseFIPS = 0
[TRACE] 2023-04-24 13:49:14.403 Aws::Endpoint::DefaultEndpointProvider [140256378881600] Endpoint bool eval parameter: UseDualStack = 0
[TRACE] 2023-04-24 13:49:14.403 Aws::Endpoint::DefaultEndpointProvider [140256378881600] Endpoint bool eval parameter: UseArnRegion = 0
[TRACE] 2023-04-24 13:49:14.403 Aws::Endpoint::DefaultEndpointProvider [140256378881600] Endpoint bool eval parameter: DisableMultiRegionAccessPoints = 0
[TRACE] 2023-04-24 13:49:14.403 Aws::Endpoint::DefaultEndpointProvider [140256378881600] Endpoint str eval parameter: Bucket = arn:aws:s3::123456789012:accesspoint/mfzwi23gnjvgw.mrap
[ERROR] 2023-04-24 13:49:14.403 HeadObject [140256378881600] A region must be set when sending requests to S3.
```

Workaround with Region=invalid-region:
```
[DEBUG] 2023-04-24 14:16:37.120 ClientConfiguration [140069699732160] Request Compression enabled
[DEBUG] 2023-04-24 14:16:37.120 ClientConfiguration [140069699732160] ClientConfiguration will use MinReqCompression: 10240
[DEBUG] 2023-04-24 14:16:37.120 ClientConfiguration [140069699732160] ClientConfiguration will use SDK Auto Resolved profile: [default] if not specified by users.
[WARN] 2023-04-24 14:16:37.120 ClientConfiguration [140069699732160] Retry Strategy will use the default max attempts.
[INFO] 2023-04-24 14:16:37.120 CurlHandleContainer [140069699732160] Initializing CurlHandleContainer with size 25
[TRACE] 2023-04-24 14:16:37.121 Aws::Endpoint::DefaultEndpointProvider [140069578106432] Endpoint str eval parameter: Region = invalid-region
[TRACE] 2023-04-24 14:16:37.121 Aws::Endpoint::DefaultEndpointProvider [140069578106432] Endpoint bool eval parameter: UseFIPS = 0
[TRACE] 2023-04-24 14:16:37.121 Aws::Endpoint::DefaultEndpointProvider [140069578106432] Endpoint bool eval parameter: UseDualStack = 0
[TRACE] 2023-04-24 14:16:37.121 Aws::Endpoint::DefaultEndpointProvider [140069578106432] Endpoint bool eval parameter: UseArnRegion = 0
[TRACE] 2023-04-24 14:16:37.121 Aws::Endpoint::DefaultEndpointProvider [140069578106432] Endpoint bool eval parameter: DisableMultiRegionAccessPoints = 0
[TRACE] 2023-04-24 14:16:37.121 Aws::Endpoint::DefaultEndpointProvider [140069578106432] Endpoint str eval parameter: Bucket = arn:aws:s3::123456789012:accesspoint/mfzwi23gnjvgw.mrap
[DEBUG] 2023-04-24 14:16:37.121 Aws::Endpoint::DefaultEndpointProvider [140069578106432] Endpoint rules engine evaluated the endpoint: https://mfzwi23gnjvgw.mrap.accesspoint.s3-global.amazonaws.com
[TRACE] 2023-04-24 14:16:37.121 Aws::Endpoint::DefaultEndpointProvider [140069578106432] Endpoint rules evaluated props: {"authSchemes":[{"disableDoubleEncoding":true,"name":"sigv4a","signingName":"s3","signingRegionSet":["*"]}]}
[TRACE] 2023-04-24 14:16:37.121 AWSClient [140069578106432] No content body, content-length headers
[DEBUG] 2023-04-24 14:16:37.121 AWSAuthSymmetricV4Signer [140069578106432] Note: Http payloads are not being signed. signPayloads=0 http scheme=https
[DEBUG] 2023-04-24 14:16:37.122 AWSClient [140069578106432] Request Successfully signed
[TRACE] 2023-04-24 14:16:37.122 CurlHttpClient [140069578106432] Making request to https://mfzwi23gnjvgw.mrap.accesspoint.s3-global.amazonaws.com/**
...
```

### Reproduction Steps

In aws-sdk-cpp/generated/tests/s3-gen-tests/S3EndpointProviderTests.cpp, remove `EpParam("Region", "us-east-1")` for any mrap test case.

### Possible Solution

Rework the file aws-sdk-cpp/tools/code-generation/endpoints/s3-2006-03-01.endpoint-rule-set.json o that MRAP arn are correctly handled.

### Additional Information/Context

Workaround is to set any (even invalid) text value in Region parameter.

### AWS CPP SDK version used

1.11.64

### Compiler and Version used

gcc 11.3

### Operating System and version

Linux 5.15