BUG: Flow.Launcher.Core.ExternalPlugins.FlowPluginException: Value cannot be null. (Parameter 'source')

### Checks

- [x] I have checked that this issue has not already been reported.

- [x] I am using the latest version of Flow Launcher.

- [ ] I am using the prerelease version of Flow Launcher.

### Problem Description

Things were working fine and now I can't browse the plugin store and if i check for plugin updates I get this error. i have reinstalled flow launcher and still get the same error.

[2025-11-13.txt](https://github.com/user-attachments/files/23539043/2025-11-13.txt)

### To Reproduce

1. ...
2. ...
3. ...

### Screenshots

_No response_

### Flow Launcher Version

2.0.2

### Windows Build Number

26200.7171

### Error Log

Flow Launcher version: 2.0.2
OS Version: 26200.7171
IntPtr Length: 8
x64: True

Python Path: C:\Users\jeff_\AppData\Roaming\FlowLauncher\Environments\Python\PythonEmbeddable-v3.11.4\pythonw.exe
Node Path:

Date: 11/13/2025 20:58:46
Exception:
Plugins Manager Exception:
Websites: https://github.com/Flow-Launcher/Flow.Launcher
Author: Jeremy Wu
Version: 2.0.2
Flow.Launcher.Core.ExternalPlugins.FlowPluginException: Value cannot be null. (Parameter 'source')
---> System.ArgumentNullException: Value cannot be null. (Parameter 'source')
at System.Linq.ThrowHelper.ThrowArgumentNullException(ExceptionArgument argument)
at System.Linq.Enumerable.Where[TSource](IEnumerable`1 source, Func`2 predicate)
at Flow.Launcher.Plugin.PluginsManager.PluginsManager.RequestInstallOrUpdateAsync(String search, CancellationToken token, Boolean usePrimaryUrlOnly) in C:\projects\flow-launcher\Plugins\Flow.Launcher.Plugin.PluginsManager\PluginsManager.cs:line 689
at Flow.Launcher.Plugin.PluginsManager.Main.QueryAsync(Query query, CancellationToken token) in C:\projects\flow-launcher\Plugins\Flow.Launcher.Plugin.PluginsManager\Main.cs:line 49
at Flow.Launcher.Core.Plugin.PluginManager.<>c__DisplayClass35_0.<b__0>d.MoveNext() in C:\projects\flow-launcher\Flow.Launcher.Core\Plugin\PluginManager.cs:line 351
--- End of stack trace from previous location ---
at Flow.Launcher.Infrastructure.Stopwatch.DebugAsync(String className, String message, Func`1 action, String methodName) in C:\projects\flow-launcher\Flow.Launcher.Infrastructure\Stopwatch.cs:line 31
at Flow.Launcher.Core.Plugin.PluginManager.QueryForPluginAsync(PluginPair pair, Query query, CancellationToken token) in C:\projects\flow-launcher\Flow.Launcher.Core\Plugin\PluginManager.cs:line 350
--- End of inner exception stack trace ---
at Flow.Launcher.Core.Plugin.PluginManager.<>c__DisplayClass35_1.b__1(ActionContext _) in C:\projects\flow-launcher\Flow.Launcher.Core\Plugin\PluginManager.cs:line 379
at Flow.Launcher.Plugin.Result.ExecuteAsync(ActionContext context) in /_/Flow.Launcher.Plugin/Result.cs:line 281
at Flow.Launcher.ViewModel.MainViewModel.OpenResultAsync(String index) in C:\projects\flow-launcher\Flow.Launcher\ViewModel\MainViewModel.cs:line 518
at CommunityToolkit.Mvvm.Input.AsyncRelayCommand.AwaitAndThrowIfFailed(Task executionTask)
at System.Threading.Tasks.Task.<>c.b__128_0(Object state)
at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs)
at System.Windows.Threading.ExceptionWrapper.TryCatchWhen(Object source, Delegate callback, Object args, Int32 numArgs, Delegate catchHandler)

Start in Plugins/Flow.Launcher.Plugin.PluginsManager/PluginsManager.cs at line 689, where RequestInstallOrUpdateAsync throws on a null source. Trace the data used by that Where call and review Main.cs line 49 for the plugin-store and update paths. Done means browsing the plugin store and checking for plugin updates no longer produce this exception.

Written by the indexing model from the issue text.