Issues while using Output from DataMapper in my next action 'HTTP'

### Severity

P1 - Critical (Blocking production)

### Describe the Bug with repro steps

Expected Behaviour:
- Should be able to use the outout from 'Data Mapper' action in my next action 'HTTP'.

Error Scenario:
- I get an error when I use the output directly from Data Mapper. Error message from the API - 'The given header was not found'.
- However, when I use a compose action and have the output from Data Mapper action into this Compose action and use the output from Compose action as input in HTTP, it works.

Please investigate why do I have to use an extra Compose action to get this to work. Please note that I am not doing anything extra in the Compose action, other than getting output from Data Mapper action.

### What type of Logic App Is this happening in?

Standard (Portal)

### Are you experiencing a regression?

_No response_

### Which operating system are you using?

Windows

### Did you refer to the TSG before filing this issue? https://aka.ms/lauxtsg

Yes

### Workflow JSON

```json
{
"definition": {
"$schema": "https://schema.management.azure.com/providers/Microsoft.Logic/schemas/2016-06-01/workflowdefinition.json#",
"actions": {
"HCM_EmpTerminationDateValidation_To_Cherwell_Notification": {
"type": "Xslt",
"kind": "DataMapper",
"inputs": {
"content": "@triggerBody()",
"map": {
"source": "LogicApp",
"name": "HCM_EmpTerminationDateValidation_To_Cherwell_Notification.xslt"
}
},
"runAfter": {}
},
"Cherwell-Notification": {
"type": "Http",
"inputs": {
"uri": "https://xxxxxxxx",
"method": "POST",
"headers": {
"Ocp-Apim-Subscription-Key": "xxxxxxxx",
"Content-Type": "application/json"
},
"body": "@body('HCM_EmpTerminationDateValidation_To_Cherwell_Notification')",
"retryPolicy": {
"type": "none"
}
},
"runAfter": {
"HCM_EmpTerminationDateValidation_To_Cherwell_Notification": [
"SUCCEEDED"
]
},
"runtimeConfiguration": {
"contentTransfer": {
"transferMode": "Chunked"
}
}
}
},
"contentVersion": "1.0.0.0",
"outputs": {},
"triggers": {
"http": {
"type": "Request",
"kind": "Http"
}
}
},
"kind": "Stateful"
}
```

### Screenshots or Videos

_No response_

### Environment

Development

### Additional context

_No response_

No repository file or test is named; start with the supplied Standard Logic App workflow JSON and reproduce the direct DataMapper-to-HTTP body path. Compare it with the Compose-mediated path and trace the DataMapper output handling; done means the HTTP action accepts the direct output without requiring Compose, with the reported header error resolved.

Written by the indexing model from the issue text.