remove Objective-C code and rename PhotoGalleryPlugin.swift

ios/Classes/PhotoGalleryPlugin.h

@@ -1,4 +0,0 @@
-#import <Flutter/Flutter.h>
-
-@interface PhotoGalleryPlugin : NSObject<FlutterPlugin>
-@end

ios/Classes/PhotoGalleryPlugin.m

@@ -1,15 +0,0 @@
-#import "PhotoGalleryPlugin.h"
-#if __has_include(<photo_gallery/photo_gallery-Swift.h>)
-#import <photo_gallery/photo_gallery-Swift.h>
-#else
-// Support project import fallback if the generated compatibility header
-// is not copied when this plugin is created as a library.
-// https://forums.swift.org/t/swift-static-libraries-dont-copy-generated-objective-c-header/19816
-#import "photo_gallery-Swift.h"
-#endif
-
-@implementation PhotoGalleryPlugin
-+ (void)registerWithRegistrar:(NSObject<FlutterPluginRegistrar>*)registrar {
-  [SwiftPhotoGalleryPlugin registerWithRegistrar:registrar];
-}
-@end

ios/Classes/PhotoGalleryPlugin.swift

@@ -4,10 +4,10 @@ import Flutter
 import UIKit
 import Photos
 
-public class SwiftPhotoGalleryPlugin: NSObject, FlutterPlugin {
+public class PhotoGalleryPlugin: NSObject, FlutterPlugin {
   public static func register(with registrar: FlutterPluginRegistrar) {
     let channel = FlutterMethodChannel(name: "photo_gallery", binaryMessenger: registrar.messenger())
-    let instance = SwiftPhotoGalleryPlugin()
+    let instance = PhotoGalleryPlugin()
     registrar.addMethodCallDelegate(instance, channel: channel)
   }