fix：1、修复bug 2、删除不用的代码和资源，sdk等

Assets/MaxSdk/Scripts/IntegrationManager/Editor/AppLovinPackageManager.cs

@@ -31,20 +31,14 @@ namespace AppLovinMax.Scripts.IntegrationManager.Editor
     {
         private const string AppLovinMediationAmazonAdapterDependenciesPath = "Amazon/Scripts/Mediations/AppLovinMediation/Editor/Dependencies.xml";
 
-#if UNITY_2019_2_OR_NEWER
         private static readonly IPackageManagerClient _upmPackageManager = new AppLovinUpmPackageManager();
-#endif
         private static readonly IPackageManagerClient _assetsPackageManager = new AppLovinAssetsPackageManager();
 
         private static IPackageManagerClient PackageManagerClient
         {
             get
             {
-#if UNITY_2019_2_OR_NEWER
                 return AppLovinIntegrationManager.IsPluginInPackageManager ? _upmPackageManager : _assetsPackageManager;
-#else
-                return _assetsPackageManager;
-#endif
             }
         }
 
@@ -110,10 +104,8 @@ namespace AppLovinMax.Scripts.IntegrationManager.Editor
             var installedNetworksInAssets = AppLovinAssetsPackageManager.GetInstalledMediationNetworks();
             installedNetworks.AddRange(installedNetworksInAssets);
 
-#if UNITY_2019_2_OR_NEWER
             var installedNetworksInPackages = AppLovinUpmPackageManager.GetInstalledMediationNetworks();
             installedNetworks.AddRange(installedNetworksInPackages);
-#endif
 
             if (IsAmazonAppLovinAdapterInstalled())
             {
@@ -174,12 +166,10 @@ namespace AppLovinMax.Scripts.IntegrationManager.Editor
         internal static void UpdateCurrentVersions(Network network)
         {
             var assetPaths = GetAssetPathListForExportPath(network.DependenciesFilePath);
-#if UNITY_2019_2_OR_NEWER
             if (HasDuplicateAdapters(assetPaths))
             {
                 ShowDeleteDuplicateAdapterPrompt(network);
             }
-#endif
 
             var currentVersions = GetCurrentVersions(assetPaths);
             network.CurrentVersions = currentVersions;
@@ -237,7 +227,6 @@ namespace AppLovinMax.Scripts.IntegrationManager.Editor
             }
         }
 
-#if UNITY_2019_2_OR_NEWER
         /// <summary>
         /// Checks whether a network has duplicate adapters installed in both the Assets folder and via UPM.
         /// </summary>
@@ -274,6 +263,9 @@ namespace AppLovinMax.Scripts.IntegrationManager.Editor
         /// otherwise, deletes the adapter from the Assets folder.</param>
         internal static void DeleteDuplicateAdapter(Network network, bool keepAssetsAdapter)
         {
+            // Skip duplicate removal logic for our plugin.
+            if (network.Name.Equals("APPLOVIN_NETWORK")) return;
+
             if (keepAssetsAdapter)
             {
                 var appLovinManifest = AppLovinUpmManifest.Load();
@@ -292,7 +284,6 @@ namespace AppLovinMax.Scripts.IntegrationManager.Editor
 
             AppLovinUpmPackageManager.ResolvePackageManager();
         }
-#endif
 
         /// <summary>
         /// Gets the current versions for a given network's dependency file paths. UPM will have multiple paths
@@ -426,7 +417,6 @@ namespace AppLovinMax.Scripts.IntegrationManager.Editor
         #endregion
     }
 
-#if UNITY_2019_2_OR_NEWER
     public class AppLovinUpmPackageManager : IPackageManagerClient
     {
         public const string PackageNamePrefixAppLovin = "com.applovin.mediation.ads";
@@ -595,8 +585,6 @@ namespace AppLovinMax.Scripts.IntegrationManager.Editor
         }
     }
 
-#endif
-
     public class AppLovinAssetsPackageManager : IPackageManagerClient
     {
         public static List<string> GetInstalledMediationNetworks()