Bump to google/bundletool@f17ce94a (#8135)

Context: https://github.com/google/bundletool/releases/tag/1.15.1
Changes: google/bundletool@1.8.1...1.15.1

We are seeing an error with API 34:

    XABBA7024: Xamarin.Tools.Zip.ZipIOException: The file 'obj\Release\android\bin\base.zip' is not a ZIP archive.

We wonder if updating `bundletool` will help. It was last updated in
989dc07.

* [tests] Update `ManifestTest.cs`

Context: https://github.com/xamarin/xamarin-android/blob/f1d59181c8daaa8d2abcdfd151b592ece49155ca/src/Xamarin.Android.Build.Tasks/Tests/Xamarin.Android.Build.Tests/ManifestTest.cs#L650-L651

The `ModifyManifest` test actually writes "too much" to the
`AndroidManifest.xml` file, removing the `<application>` element,
causing the latest version of `bundletool` to error with:

    BT One element <application> was expected, but none were found.

To solve this, let's update the test to not overwrite any existing XML content.

Configuration.props

@@ -148,7 +148,7 @@
     <XAPlatformToolsPackagePrefix Condition=" '$(HostOS)' == 'Darwin' "></XAPlatformToolsPackagePrefix>
     <XAPlatformToolsVersion>34.0.1</XAPlatformToolsVersion>
     <XAIncludeProprietaryBits Condition="'$(XAIncludeProprietaryBits)' == ''">False</XAIncludeProprietaryBits>
-    <XABundleToolVersion Condition="'$(XABundleToolVersion)' == ''">1.8.1</XABundleToolVersion>
+    <XABundleToolVersion Condition="'$(XABundleToolVersion)' == ''">1.15.1</XABundleToolVersion>
     <XAPackagesDir Condition=" '$(XAPackagesDir)' == '' And '$(NUGET_PACKAGES)' != ''">$(NUGET_PACKAGES)</XAPackagesDir>
     <XAPackagesDir Condition=" '$(XAPackagesDir)' == '' And '$(HostOS)' == 'Windows'">$(userprofile)\.nuget\packages</XAPackagesDir>
     <XAPackagesDir Condition=" '$(XAPackagesDir)' == '' And '$(HostOS)' != 'Windows'">$(HOME)/.nuget/packages</XAPackagesDir>

src/Xamarin.Android.Build.Tasks/Tests/Xamarin.Android.Build.Tests/ManifestTest.cs

@@ -669,9 +669,16 @@ public void ModifyManifest ([Values (true, false)] bool isRelease)
 	<_Permissions Include=""&lt;uses-permission android:name=&quot;android.permission.READ_CONTACTS&quot; /&gt;"" />
 </ItemGroup>
 <Target Name=""_Foo"">
+	<XmlPeek Query=""/manifest/*"" XmlInputPath=""$(IntermediateOutputPath)android\AndroidManifest.xml"">
+		<Output TaskParameter=""Result"" ItemName=""_XmlNodes"" />
+	</XmlPeek>
+	<PropertyGroup>
+		<_ExistingXml>@(_XmlNodes, ' ')</_ExistingXml>
+		<_NewXml>@(_Permissions, ' ')</_NewXml>
+	</PropertyGroup>
 	<XmlPoke
 		XmlInputPath=""$(IntermediateOutputPath)android\AndroidManifest.xml""
-		Value=""@(_Permissions)""
+		Value=""$(_ExistingXml)$(_NewXml)""
 		Query=""/manifest""
 		Namespaces=""$(Namespace)""
 	/>