Send with raw parameters

Summary:
On Android we already had an API to send raw arguments i.e. raw json as params.

This just adds feature parity on iOS.

Reviewed By: LukeDefeo

Differential Revision: D41433777

fbshipit-source-id: abd47f987b9e2b451100e81acf6fea61cd876807

iOS/FlipperKitTestUtils/FlipperConnectionMock.m

@@ -38,6 +38,10 @@
   [self sendInternal:method withParams:params loggedTo:&_sent];
 }
 
+- (void)send:(NSString*)method withRawParams:(NSString*)params {
+  [self sendInternal:method withParams:params loggedTo:&_sent];
+}
+
 - (void)send:(NSString*)method withArrayParams:(NSArray*)params {
   [self sendInternal:method withParams:params loggedTo:&_sentWithArray];
 }