Remove hard-coded .NET Sdk version for mgmt pipelines (#14799)

Author: weshaggard

eng/pipelines/mgmt.yml

@@ -143,7 +143,6 @@ pr:
     - eng/pipelines/templates/jobs/archetype-sdk-mgmt.yml
 
 variables:
-  DotNetCoreSDKVersion: '2.2.202'
   skipComponentGovernanceDetection: true
   msBuildLogDir: msbuildlogs
   loggingArgs: '/clp:ShowtimeStamp /flp:LogFile=$(msBuildLogDir)/msbuild.normal.log;Verbosity=normal /flp1:Summary;Verbosity=minimal;LogFile=$(msBuildLogDir)/msbuild.sum.log /flp2:warningsonly;logfile=$(msBuildLogDir)/msbuild.wrn.log /flp3:errorsonly;logfile=$(msBuildLogDir)/msbuild.err.log'

eng/pipelines/templates/jobs/archetype-sdk-mgmt.yml

@@ -3,10 +3,6 @@ jobs:
     pool:
       vmImage: windows-2019
     steps:
-      - task: UseDotNet@2
-        displayName: "Use .NET Core sdk $(DotNetCoreSDKVersion)"
-        inputs:
-          version: "$(DotNetCoreSDKVersion)"
       #- script: "echo $(system.pullrequest.pullrequestnumber), https://github.com/$(build.repository.id), https://github.com/$(build.repository.ID)"
       - script: |
           if "$(BuildConfiguration)" == "Release" (set SkipTests=true) else (set SkipTests=false)
@@ -49,10 +45,6 @@ jobs:
       vmImage: "$(OSVmImage)"
     steps:
       - template: /eng/common/pipelines/templates/steps/verify-agent-os.yml
-      - task: UseDotNet@2
-        displayName: "Use .NET Core sdk $(DotNetCoreSDKVersion)"
-        inputs:
-          version: "$(DotNetCoreSDKVersion)"
       - script: "echo $(system.pullrequest.pullrequestnumber), https://github.com/$(build.repository.id), https://github.com/$(build.repository.ID)"
       - script: "dotnet msbuild mgmt.proj /v:n /t:RunTests /p:Scope=${{parameters.Scope}} /p:ForPublishing=$(ShouldPublish) /clp:ShowtimeStamp $(RPScopeArgs)"
         displayName: "Build & Run Tests"