chore: Modify windows defender settings on CI

[filzrev]

On Windows CI environment.
Set-MpPreference -DisableRealtimeMonitoring $true command sometimes failed with following error.
(e.g. https://github.com/dotnet/BenchmarkDotNet/actions/runs/21105743318/job/60696964630)

Set-MpPreference : Operation failed with the following error: 0x800106ba. Operation: Set-MpPreference. Target: 
DisableRealtimeMonitoring.
At C:\a\_temp\59c177be-e82b-4480-9398-c47727230783.ps1:2 char:1
+ Set-MpPreference -DisableRealtimeMonitoring $true
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : NotSpecified: (MSFT_MpPreference:root\Microsoft\...FT_MpPreference) [Set-MpPreference],  
   CimException
    + FullyQualifiedErrorId : HRESULT 0x800106ba,Set-MpPreference

It seems there is some race conditions that can't disable Windows Defender.

What's changed in this PR

1. Remove code that disabling Windows Defender.
2. Add following exclude path settings instead.
   2.1. $env:GITHUB_WORKSPACE
   2.2. $env:Temp

I though this approach is less likely to fail than DisableRealtimeMonitoring.

If it failed with this PR settings.
It need to add retry logics to wait Windows Defender service is available.