Modules with operation objects that return enum type responses fail to build

[peombwa]

Given the following OpenAPI v3.0.1 document with an operation object that returns an enum type as its response:

paths:
  /deviceManagement/chromeOSOnboardingSettings/microsoft.graph.connect:
    post:
      tags:
        - deviceManagement.Actions
      summary: Invoke action connect
      operationId: deviceManagement.chromeOSOnboardingSettings_connect
      requestBody:
        description: Action parameters
        content:
          application/json:
            schema:
              type: object
              properties:
                ownerUserPrincipalName:
                  type: string
                  nullable: true
        required: true
      responses:
        '200':
          description: Success
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/microsoft.graph.chromeOSOnboardingStatus'
        default:
          $ref: '#/components/responses/error'
      x-ms-docs-operation-type: action
components:
  schemas:
    microsoft.graph.chromeOSOnboardingStatus:
      title: chromeOSOnboardingStatus
      enum:
        - unknown
        - inprogress
        - onboarded
        - failed
        - offboarding
        - unknownFutureValue
      type: string
      description: The onboarding status of the tenant.
      x-ms-enum:
        name: chromeOSOnboardingStatus
        modelAsString: false
        values:
          - value: unknown
            description: Unknown
            name: unknown
...(shortened)...

Current Behavior

The generated module fails with the following compilation error when running .\generated\build-module.ps1 script:

Creating isolated process...
Cleaning build folders...
Compiling module...
F:\temp\AutoREST.Test\generated\generated\api\DeviceManagementActions.cs(82,50): 
error CS1503: Argument 2: cannot convert from 'System.Threading.Tasks.Task<string>' to 'System.Threading.Tasks.Task<Sample.API.Support.ChromeOSOnboardingStatus>' [F:\temp\Aut 
oREST.Test\generated\DeviceActions.csproj]
Write-Error: F:\temp\AutoREST.Test\generated\build-module.ps1:76:5

Expected Behavior

The generated module should build successfully when an operation returns an enum type as its response.

Repro Steps

Sample OpenAPI document - https://gist.github.com/peombwa/b2758d2425205d0e51c9bf8cae1fbec7

#1. CD to output directory
#2. Generate module using sample OpenAPI document 
autorest --powershell --input-file:https://gist.githubusercontent.com/peombwa/b2758d2425205d0e51c9bf8cae1fbec7/raw/d6fb8178356c2cb9415de828a58450804391d269/DeviceManagement.yml
#3. Build generated module
.\generated\build-module.ps1
#4. Compilation error is thrown
cannot convert from 'System.Threading.Tasks.Task<string>' to 'System.Threading.Tasks.Task<Sample.API.Support.ChromeOSOnboardingStatus>'

Environment

AutoRest code generation utility [cli version: 3.6.2; node: v14.11.0]
(C) 2018 Microsoft Corporation.
https://aka.ms/autorest
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