DMS Endpoint propagated tags are deleted instead of being updated

### Name of the resource

AWS::DMS::Endpoint

### Resource Name

_No response_

### Issue Description

When creating a DMS Endpoint via CloudFormation, with tags defined at the stack level, the resource is created correctly with the defined tags; but if the stack is updated to change the tags, the user-defined tags are REMOVED and new tags are not added.

This breaks reporting and tag compliance policies.

### Expected Behavior

CloudFormation should maintain resource tags correctly.

### Observed Behavior

CloudFormation deletes removed tags but does not add new tags

### Test Cases

* create a stack with a single DMS endpoint (see template below) using the command-line `aws cloudformation deploy --template-file template.yml --stack-name dms-endpoint-test --tags mytag:something=other`
* Check the endpoint resource tags -- in addition to the standard CloudFormation tags (`stack-id`, `stack-name`, `logical-id`) you will see the user-defined tag
* update the same stack in place, making no other changes to the template, using the command line `aws cloudformation deploy --template-file template.yml --stack-name dms-endpoint-test --tags mynewtag:beeps=eggplant`

After the stack update, the Endpoint will only have the CloudFormation tags -- both the original user-defined tag and the new one are missing. The first tag _should_ be missing, the second tag should not.

Subsequent updates to the resource don't add back ANY user-defined tags.

Setting tags explicitly in the template does work, but this is core functionality that is clearly broken.

### Other Details

```yaml
AWSTemplateFormatVersion: 2010-09-09
Description: Replicate DMS Endpoint tagging failure

Resources:
Endpoint:
Type: AWS::DMS::Endpoint
Properties:
EndpointType: source
EngineName: oracle
ServerName: florble.poons
Port: 1234
Username: meeply
Password: plums
DatabaseName: toad
SslMode: none
```

No repository file or test is mentioned. Reproduce the issue with the supplied template using `aws cloudformation deploy`, first with `mytag:something=other` and then with `mynewtag:beeps=eggplant`; done means removed tags disappear while new propagated tags remain on the AWS::DMS::Endpoint.

Written by the indexing model from the issue text.