Bump $(AndroidNetPreviousVersion) to 34.0.79 (#8693)

Context: fd47b02
Context: https://dotnet.microsoft.com/platform/support/policy/maui

Changes: d12da3a...87e4a6d

  * 87e4a6d89: [release/8.0.1xx] localization changes for `XA1039` (#8674)
  * f61c76030: [workload] Allow installation on linux-arm64 (#8500)
  * 4cdf1e018: [Xamarin.Android.build.Tasks] `<CheckDuplicateJavaLibraries/>` ignores `repackaged.jar` (#8664)
  * 77ac82a11: [release/8.0.1xx] [Xamarin.Android.Build.Tasks] XA1039 warning for Android.Support (#8648)
  * c22c17fbe: [Xamarin.Android.Build.Tasks] fix warning when missing `proguard-android.txt` (#8641)
  * 31f031a67: Localized file check-in by OneLocBuild Task (#8643)
  * 3da479192: LEGO: Merge pull request 8642
  * dbf100d49: Update a number of l18n files (#8633)
  * d2da5bf4e: Bump com.android.tools:r8 from 8.1.72 to 8.2.33 (#8577)
  * 9f9114afc: Bump com.android.tools:r8 from 8.1.56 to 8.1.72 (#8532)
  * 666777248: Fix ServerCertificateCustomValidator on API 21-23 (#8637)
  * 940f059b8: [Mono.Android] Fix ServerCertificateCustomValidator (#8594)
  * 351bfa3f0: Bump to dotnet/runtime@a6e4834d53 8.0.1 (#8616)
  * 64363367d: [Microsoft.Android.Templates] New files should open editor (#8623)
  * 26752564d: Bump to dotnet/installer@461c776642 8.0.101-servicing.23614.6
  * 6972027f0: Localized file check-in by OneLocBuild Task (#8589)
  * 73efcfcad: [Xamarin.Android.Buid.Tasks] don't set $(PublishSelfContained) for .NET 9 (#8565)
  * 3333306b8: LEGO: Merge pull request 8587
  * 38e950b41: Localized file check-in by OneLocBuild Task (#8576)
  * 607115fd5: LEGO: Merge pull request 8575
  * a1fd1b2cb: Localized file check-in by OneLocBuild Task (#8570)
  * c020626b0: [Xamarin.Android.Build.Tasks] Update XA5207 for VSCode (#8494)
  * b0aab545a: Bump to dotnet/installer@822071c28a 8.0.101-servicing.23578.14 (#8558)


The .NET MAUI Support policy, which covers .NET Android, states:

> A major version of .NET MAUI receives support for a minimum of 6
> months after a successor (the next major release) ships.

meaning that a given version of .NET Android only needs to support
building `$(TargetFramework)` values for the current .NET Android
version and the previous .NET Android version.

Meanwhlie, from fd47b02:

> We currently have a hard dependency between:
> 
>   * `Xamarin.Android.Build.Tasks.dll`
>   * `libmonodroid.so`

…in order to safely build projects targeting the previous .NET Android
version with the current .NET Android version, the current .NET Android
version workload *includes the previous workload version contents*.

The `$(AndroidNetPreviousVersion)` MSBuild property specifies the
.NET Android SDK version, as obtained from `dotnet workllad list`,
which should be used to build previous `$(TargetFramework)` versions.

`$(AndroidNetPreviousVersion)` should be updated in
xamarin-android/main whenever a .NET servicing release for the previous
.NET version is shipped.

.NET Android 34.0.79 will be shipped as part of .NET 8.0.2.
Update `$(AndroidNetPreviousVersion)` to so that .NET 9 previews use
the latest .NET 8 workload contents.

Configuration.props

@@ -43,7 +43,7 @@
     <DebugType Condition=" '$(DebugType)' == '' ">portable</DebugType>
     <Deterministic Condition=" '$(Deterministic)' == '' ">True</Deterministic>
     <LangVersion Condition=" '$(LangVersion)' == '' ">latest</LangVersion>
-    <AndroidNetPreviousVersion Condition=" '$(AndroidNetPreviousVersion)' == '' ">34.0.56</AndroidNetPreviousVersion>
+    <AndroidNetPreviousVersion Condition=" '$(AndroidNetPreviousVersion)' == '' ">34.0.79</AndroidNetPreviousVersion>
   </PropertyGroup>
   <PropertyGroup Condition=" '$(HostOS)' == '' ">
     <HostOS Condition="$([MSBuild]::IsOSPlatform('windows'))">Windows</HostOS>