Add merge.targets to embed proto JARs and remove PackageReference

Co-authored-by: jonathanpeppers <840039+jonathanpeppers@users.noreply.github.com>

Author: Copilot

source/androidx.health.connect/connect-client/merge.targets

@@ -0,0 +1,12 @@
+<Project>
+  <ItemGroup>
+    <!-- Include the proto JAR files directly into this binding -->
+    <InputJar Include="..\..\externals\androidx.health.connect\connect-client-proto.jar" />
+    <InputJar Include="..\..\externals\androidx.health.connect\connect-client-external-protobuf.jar" />
+  </ItemGroup>
+  
+  <ItemGroup>
+    <!-- Remove the PackageReference to the proto package since we're embedding it -->
+    <PackageReference Remove="Xamarin.AndroidX.Health.Connect.Client.Proto" />
+  </ItemGroup>
+</Project>