Fully convert ExtensionDiscovery to be injectable

- To fix unit tests

Signed-off-by: Sebastian Malton <sebastian@malton.name>

packages/core/src/common/ipc/extension-handling.ts

@@ -1,6 +0,0 @@
-/**
- * Copyright (c) OpenLens Authors. All rights reserved.
- * Licensed under MIT License. See LICENSE in root directory for more information.
- */
-
-export const extensionDiscoveryStateChannel = "extension-discovery:state";