fix(test-runner-core): enable file watcher in manual mode

Author: tmsns

.changeset/famous-pens-flash.md

@@ -0,0 +1,5 @@
+---
+'@web/test-runner-core': patch
+---
+
+fix: enable file watcher in manual mode

packages/test-runner-core/src/server/TestRunnerServer.ts

@@ -46,7 +46,7 @@ export class TestRunnerServer {
 
       mimeTypes: config.mimeTypes,
 
-      disableFileWatcher: !config.watch,
+      disableFileWatcher: !config.watch && !config.manual,
 
       middleware: [
         watchFilesMiddleware({ runSessions, sessions, rootDir, fileWatcher: this.fileWatcher }),