Improve error handling for invalid plugin.json files

Previously, installing a plugin with an invalid or corrupted plugin.json would cause an unhandled exception. Now, deserialization errors are caught, a user-friendly error message is shown, and the exception is logged. Added a new localized error message for this scenario in en.xaml.

Author: Jack251970

Flow.Launcher.Core/Plugin/PluginManager.cs

@@ -896,7 +896,19 @@ internal static bool InstallPlugin(UserPlugin plugin, string zipFilePath, bool c
                 return false;
             }
 
-            var newMetadata = JsonSerializer.Deserialize<PluginMetadata>(File.ReadAllText(metadataJsonFilePath));
+            PluginMetadata newMetadata;
+            try
+            {
+                newMetadata = JsonSerializer.Deserialize<PluginMetadata>(File.ReadAllText(metadataJsonFilePath));
+            }
+            catch (Exception ex)
+            {
+                PublicApi.Instance.ShowMsgError(Localize.failedToInstallPluginTitle(plugin.Name),
+                    Localize.pluginJsonInvalidOrCorrupted());
+                PublicApi.Instance.LogException(ClassName,
+                    $"Failed to deserialize plugin metadata for plugin {plugin.Name} from file {metadataJsonFilePath}", ex);
+                return false;
+            }
 
             if (SameOrLesserPluginVersionExists(newMetadata))
             {

Flow.Launcher/Languages/en.xaml

@@ -234,6 +234,7 @@
     <system:String x:Key="errorCreatingSettingPanel">Error creating setting panel for plugin {0}:{1}{2}</system:String>
     <system:String x:Key="pluginMinimumAppVersionUnsatisfiedTitle">{0} requires Flow {1}+ version to run</system:String>
     <system:String x:Key="pluginMinimumAppVersionUnsatisfiedMessage">Flow does not meet the minimum version requirements for {0} to run. Do you want to continue installing it? We recommend updating Flow to the latest version to ensure that {0} works without issues.</system:String>
+    <system:String x:Key="pluginJsonInvalidOrCorrupted">Failed to install plugin because plugin.json is invalid or corrupted</system:String>
 
     <!--  Setting Plugin Store  -->
     <system:String x:Key="pluginStore">Plugin Store</system:String>