Should also check if there are no external projects before skipping scheduling

Fixes failing tests

Author: sheetalkamat

src/server/editorServices.ts

@@ -930,7 +930,8 @@ namespace ts.server {
 
         /*@internal*/
         delayEnsureProjectForOpenFiles() {
-            if (!this.openFiles.size) return;
+            // If no open files or no external project, do not schedule
+            if (!this.openFiles.size && !this.externalProjects.length && !this.externalProjectToConfiguredProjectMap.size) return;
             this.pendingEnsureProjectForOpenFiles = true;
             this.throttledOperations.schedule(ensureProjectForOpenFileSchedule, /*delay*/ 2500, () => {
                 if (this.pendingProjectUpdates.size !== 0) {