`_TransformWebConfig` target should not run if `IsPublishable` is `false`

[afscrome]

Describe the bug

The _TransformWebConfig target shouldn't run on dotnet publish when IsPublishable is set to false.

The below example is slightly contrived as it doesn't make sense to run dotnet publish on a single project with IsPublishable set to false, but this scenario can be hit if you have a solution with multiple projects, and one of those has IsPublishable set to false.

To Reproduce

I can reproduce this on both 10 preview 6, and 8.0.404.

1. dotnet new web
2. dotnet publish /p:IsPublishable=false -bl

Expected results: should be able to run publish and have it be a no op.

Actual Results: _TransformWebConfig task tries to run, and fails due to missing files (see error below)

Exceptions (if any)

    C:\Program Files\dotnet\sdk\10.0.100-preview.6.25358.103\Sdks\Microsoft.NET.Sdk.Publish\targets\TransformTargets\Microsoft.NET.Sdk.Publish.TransformFiles.targets(50,5): error MSB4018:
      The "TransformWebConfig" task failed unexpectedly.
      System.IO.DirectoryNotFoundException: Could not find a part of the path 'C:\Temp\new\bin\Release\net10.0\publish\w
      eb.config'.
         at Microsoft.Win32.SafeHandles.SafeFileHandle.CreateFile(String fullPath, FileMode mode, FileAccess access, Fil
      eShare share, FileOptions options)
         at Microsoft.Win32.SafeHandles.SafeFileHandle.Open(String fullPath, FileMode mode, FileAccess access, FileShare
       share, FileOptions options, Int64 preallocationSize, Nullable`1 unixCreateMode)
         at System.IO.Strategies.OSFileStreamStrategy..ctor(String path, FileMode mode, FileAccess access, FileShare sha
      re, FileOptions options, Int64 preallocationSize, Nullable`1 unixCreateMode)
         at System.IO.Strategies.FileStreamHelpers.ChooseStrategyCore(String path, FileMode mode, FileAccess access, Fil
      eShare share, FileOptions options, Int64 preallocationSize, Nullable`1 unixCreateMode)
         at System.IO.FileStream..ctor(String path, FileMode mode)
         at Microsoft.NET.Sdk.Publish.Tasks.TransformWebConfig.Execute()
         at Microsoft.Build.BackEnd.TaskExecutionHost.Execute()
         at Microsoft.Build.BackEnd.TaskBuilder.ExecuteInstantiatedTask(TaskExecutionHost taskExecutionHost, TaskLogging
      Context taskLoggingContext, TaskHost taskHost, ItemBucket bucket, TaskExecutionMode howToExecuteTask)

Further technical details

.NET SDK:
 Version:           10.0.100-preview.6.25358.103
 Commit:            75972a5ba7
 Workload version:  10.0.100-manifests.6616851e
 MSBuild version:   17.15.0-preview-25358-103+75972a5ba

Runtime Environment:
 OS Name:     Windows
 OS Version:  10.0.22621
 OS Platform: Windows
 RID:         win-x64
 Base Path:   C:\Program Files\dotnet\sdk\10.0.100-preview.6.25358.103\

.NET workloads installed:
 [aspire]
   Installation Source: VS 17.14.36301.6
   Manifest Version:    8.2.2/8.0.100
   Manifest Path:       C:\Program Files\dotnet\sdk-manifests\8.0.100\microsoft.net.sdk.aspire\8.2.2\WorkloadManifest.json
   Install Type:              Msi

Configured to use workload sets when installing new manifests.
Workloads are configured to install and update using workload versions, but none were found. Run "dotnet workload restore" to install a workload version.

Host:
  Version:      10.0.0-preview.6.25358.103
  Architecture: x64
  Commit:       75972a5ba7

.NET SDKs installed:
  6.0.428 [C:\Program Files\dotnet\sdk]
  8.0.412 [C:\Program Files\dotnet\sdk]
  9.0.107 [C:\Program Files\dotnet\sdk]
  9.0.205 [C:\Program Files\dotnet\sdk]
  9.0.302 [C:\Program Files\dotnet\sdk]
  10.0.100-preview.6.25358.103 [C:\Program Files\dotnet\sdk]

.NET runtimes installed:
  Microsoft.AspNetCore.App 6.0.36 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 7.0.7 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 7.0.20 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 8.0.18 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 9.0.6 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 9.0.7 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 10.0.0-preview.6.25358.103 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.NETCore.App 6.0.36 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 8.0.18 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 8.0.19 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 9.0.6 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 9.0.7 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 10.0.0-preview.6.25358.103 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.WindowsDesktop.App 6.0.36 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 8.0.18 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 9.0.6 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 9.0.7 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 10.0.0-preview.6.25358.103 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]

Other architectures found:
  x86   [C:\Program Files (x86)\dotnet]
    registered at [HKLM\SOFTWARE\dotnet\Setup\InstalledVersions\x86\InstallLocation]

Environment variables:
  Not set

global.json file:
  Not found

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