[Custom MCP Connector] Creation of new connections doesn't include auth drop-down

### Severity

P2 - High (Major functionality broken)

### MCP Server Creation Source

MCP Server in Logic Apps

### Describe the Bug with repro steps

Expected behavior:
- When creating a new connection using a custom MCP connector, the user should be allowed to choose their auth type from a dropdown
- If the custom MCP connector is system- or user-assigned managed identity enabled, these options should appear in the drop down
- The user creates the connection and the listTools api returns the tools available via the MCP

Actual behavior:
- No auth options are given when a user opts to create a connection
- Once the connection is created, the listTools API returns an error due to the fact that the needed-managed identity wasn't included as part of the call
- If the user adds the connection in spite of the listTools failure, the user then has the opportunity in the next screen to add the system/user-assigned identity to the connection.

Steps to reproduce:
- Create a consumption logic app in the Brazil South region
- Add system and user assigned identities to the logic app
- Edit the workflow in the new designer mode
- Add a trigger and an agent
- In the agent, attempt to add a tool
- Choose from MCP servers
- Choose from Custom options
- Choose an existing Custom MCP server
- Click the "Create a new connection" button
- Observer the lack of a an auth options dropdown
- Create the connection
- Hit next and observer the listTools api error
- Click "Add"
- Observe the option to choose a managed identity

Resource details:
- Subscription Id: a5e1babd-443b-4ff3-9e68-92fa517782df
- Logic App Id: /subscriptions/a5e1babd-443b-4ff3-9e68-92fa517782df/resourceGroups/XiaoyuTestAgentConsumptionWestus3_group/providers/Microsoft.Logic/workflows/la-stephen-bs
- Region: Brazil South

### Screenshots or Videos

**Choose Custom MCP Server:**

**Create Connection:**

**No Authentication Options**

### Environment

- Edge

### Are you experiencing a regression?

_No response_

### Additional context

_No response_