Disable Git.Build.targets

Was pulling my hair out over this thing...

This caused nonsensical errors from the dotnet/sdk:

    test.csproj warning MSB4243: The NuGet-based SDK resolver failed to run because NuGet assemblies could not be located.  Check your installation of MSBuild or set the environment variable "MSBUILD_NUGET_PATH" to the folder that contains the required NuGet assemblies. Could not find file 'd:\agent\1\s\bin\dotnet\sdk-manifests\6.0.100\gitinfo\WorkloadManifest.json'.

`gitinfo` was being dropped in the `dotnet/sdk-manifests` folder, and
it's trying to be loaded as a workload:

    sdk-manifests\6.0.100\gitinfo\WorkloadManifest.json

Directory.Build.targets

@@ -1,5 +1,5 @@
 <Project>
-  <Import Condition="'$(SampleProject)' != 'true' and '$(CI)' == 'true'" Project="eng\Git.Build.targets" />
+  <Import Condition="'$(SampleProject)' != 'true' and '$(CI)' == 'true' and '$(DisableGitInfo)' != 'true' " Project="eng\Git.Build.targets" />
   <Import Condition="'$(SampleProject)' != 'true' and '$(CI)' == 'true' " Project="eng\Version.targets" />
   <Import Project="eng\AndroidX.targets" />
   <Import Project="eng\Microsoft.Extensions.targets" />

src/DotNet/Dependencies/Packs.csproj

@@ -1,6 +1,7 @@
 <Project Sdk="Microsoft.Build.NoTargets">
   <PropertyGroup>
     <TargetFramework>netstandard2.0</TargetFramework>
+    <DisableGitInfo>true</DisableGitInfo>
   </PropertyGroup>
   <ItemGroup>
     <PackageDownload Include="Microsoft.Android.Ref"            Version="[$(MicrosoftAndroidSdkPackageVersion)]" />

src/DotNet/Dependencies/Workloads.csproj

@@ -1,6 +1,7 @@
 <Project Sdk="Microsoft.Build.NoTargets">
   <PropertyGroup>
     <TargetFramework>netstandard2.0</TargetFramework>
+    <DisableGitInfo>true</DisableGitInfo>
   </PropertyGroup>
   <ItemGroup>
     <PackageDownload Include="Microsoft.NET.Workload.Android"     Version="[$(MicrosoftAndroidSdkPackageVersion)]" />

src/DotNet/DotNet.csproj

@@ -2,6 +2,7 @@
   <PropertyGroup>
     <TargetFramework>netstandard2.0</TargetFramework>
     <IsPackable>false</IsPackable>
+    <DisableGitInfo>true</DisableGitInfo>
     <MauiOutputPath>$([System.IO.Path]::GetFullPath('$(MSBuildThisFileDirectory)../../bin/'))</MauiOutputPath>
     <DotNetDirectory>$(MauiOutputPath)dotnet/</DotNetDirectory>
     <DotNetToolPath>$(DotNetDirectory)dotnet</DotNetToolPath>