Fix IllegalStateException crash in WebSocketModule.java

Summary:- Motivation: The WebSocket implementation on Android crashes the app when an attempt is made to write on a web socket that was closed due to a spotty connection. We found this issue by using Pusher, which is built on WebSockets. The following stack trace reveals that the WebSocketModule doesn't catch the case of a closed connection, when a consumer attempts to write:
```sh
Fatal Exception: java.lang.IllegalStateException: closed
       at com.squareup.okhttp.internal.ws.RealWebSocket.sendMessage(RealWebSocket.java:109)
       at com.facebook.react.modules.websocket.WebSocketModule.send(WebSocketModule.java:176)
       at java.lang.reflect.Method.invoke(Method.java)
       at java.lang.reflect.Method.invoke(Method.java:372)
       at com.facebook.react.bridge.BaseJavaModule$JavaMethod.invoke(BaseJavaModule.java:249)
       at com.facebook.react.bridge.NativeModuleRegistry$ModuleDefinition.call(NativeModuleRegistry.java:158)
       at com.facebook.react.bridge.NativeModuleRegistry.call(NativeModuleReg
Closes https://github.com/facebook/react-native/pull/6301

Differential Revision: D3016099

fb-gh-sync-id: 838dd9d2e5e5b7a4e2242fa6de5658dfdaf24f55
shipit-source-id: 838dd9d2e5e5b7a4e2242fa6de5658dfdaf24f55

ReactAndroid/src/main/java/com/facebook/react/modules/websocket/WebSocketModule.java

@@ -10,6 +10,7 @@
 package com.facebook.react.modules.websocket;
 
 import java.io.IOException;
+import java.lang.IllegalStateException;
 import javax.annotation.Nullable;
 
 import com.facebook.common.logging.FLog;
@@ -176,7 +177,7 @@ public class WebSocketModule extends ReactContextBaseJavaModule {
       client.sendMessage(
         WebSocket.PayloadType.TEXT,
         new Buffer().writeUtf8(message));
-    } catch (IOException e) {
+    } catch (IOException | IllegalStateException e) {
       notifyWebSocketFailed(id, e.getMessage());
     }
   }