Allow SonarFlowReporter to use an existing Flipper Network Plugin if …

…any was presented, or fall to DI

Summary:
After adding Graphservice to AMA Android, I tried to integrate Flipper network plugin to capture GS requests and send them to Flipper. However, I noticed that AMA uses Catalyst shell package which will [init Flipper initially](https://www.internalfb.com/code/fbsource/[56757675f594]/fbandroid/java/com/facebook/catalyst/shell/FbReactApplicationBaseSonarUtil.java?lines=25-39) so any attempt to use DI to create a new network plugin to catch GS traffic won't work since Flipper singleton will relay on the first network plugin that was created before DI.
This changes will resolve the problem, before letting DI create a new network plugin object, it will look for an existing one so it reuse it, if non were declared then it will create a new instance.

Reviewed By: WilliamY97

Differential Revision: D57799647

fbshipit-source-id: 6d059bcc63060f832d2c0bceeeff5f216db6a7a2

android/plugins/network/src/main/java/com/facebook/flipper/plugins/network/NetworkFlipperPlugin.java

@@ -19,8 +19,7 @@
 public class NetworkFlipperPlugin extends BufferingFlipperPlugin implements NetworkReporter {
   public static final String ID = "Network";
   private static final int MAX_BODY_SIZE_IN_BYTES = 1024 * 1024;
-
-  private final List<NetworkResponseFormatter> mFormatters;
+  private List<NetworkResponseFormatter> mFormatters;
 
   public NetworkFlipperPlugin() {
     this(null);
@@ -35,6 +34,10 @@ public String getId() {
     return ID;
   }
 
+  public void setFormatters(List<NetworkResponseFormatter> formatters) {
+    mFormatters = formatters;
+  }
+
   @Override
   public void reportRequest(final RequestInfo requestInfo) {
     (new ErrorReportingRunnable(getConnection()) {