Issue adding Custom MCP Server Action

### Severity

P3 - Medium (Minor functionality affected)

### MCP Server Creation Source

MCP Server in Api Center

### Describe the Bug with repro steps

Expected behavior:
- Workflow must be successfully saved from the Designer view.
- Existing Custom MCP Server connections should be listed correctly when adding the Custom MCP Server action.
- Newly created connections should generate a complete and valid connection block automatically.

Actual behavior:

On Old View:
- When trying to add the Custom MCP Server action, the existing MCP servers are not listed. Instead, unrelated or cached entries appear.
- When attempting to create a new connection, the generated code view contains an incomplete connection block such as:

```json
{
"type": "McpClientTool",
"kind": "Builtin"
}
```

- The workflow cannot be saved and throws the following error:

Workflow Validation Operations Error
Error occurred while validating workflow operations parameters.

On New View:
- Existing MCP Server connections are also not listed.
- The UI prompts to create a new connection instead.
- Creating a new connection also fails, and the code view again contains the same incomplete connection block shown above.
- Workflow save operation fails.

Microsoft Support provided the correct connection block separately, and after manually updating the workflow JSON in Code View, the workflow was saved successfully and started working.

Steps to reproduce:
1. Open Logic Apps Designer (Old View or New View).
2. Add the “Custom MCP Server” action.
3. Observe that existing MCP Server connections are not listed.
4. Attempt to create a new connection.
5. Check the generated Code View and observe the incomplete connection block.
6. Try saving the workflow.
7. Observe the Workflow Validation Operations Error.

Resource details (if applicable):
- Subscription Id: c142eff4-3eb8-4e84-a108-8f69e69717d0
- Logic App Id: /subscriptions/c142eff4-3eb8-4e84-a108-8f69e69717d0/resourceGroups/cis-automation-platform-dev/providers/Microsoft.Web/sites/tobedeleted101
- Region: East US

Additional context:
- Severity is marked as P3 only because Microsoft Support provided a manual workaround. Without the workaround, this would be a major UI/productivity issue since workflows cannot be configured or saved through the Designer UI.

### Screenshots or Videos

_No response_

### Environment

Edge

### Are you experiencing a regression?

_No response_

### Additional context

_No response_