add FLT prefix to the ios class

Author: amirh

packages/webview_flutter/ios/Classes/WebviewFlutterPlugin.h

@@ -4,5 +4,5 @@
 
 #import <Flutter/Flutter.h>
 
-@interface WebviewFlutterPlugin : NSObject<FlutterPlugin>
+@interface FLTWebviewFlutterPlugin : NSObject<FlutterPlugin>
 @end

packages/webview_flutter/ios/Classes/WebviewFlutterPlugin.m

@@ -4,12 +4,12 @@
 
 #import "WebviewFlutterPlugin.h"
 
-@implementation WebviewFlutterPlugin
+@implementation FLTWebviewFlutterPlugin
 + (void)registerWithRegistrar:(NSObject<FlutterPluginRegistrar>*)registrar {
   FlutterMethodChannel* channel = [FlutterMethodChannel
       methodChannelWithName:@"webview_flutter"
             binaryMessenger:[registrar messenger]];
-  WebviewFlutterPlugin* instance = [[WebviewFlutterPlugin alloc] init];
+  FLTWebviewFlutterPlugin* instance = [[FLTWebviewFlutterPlugin alloc] init];
   [registrar addMethodCallDelegate:instance channel:channel];
 }