fix: apply temporary fix to handle undefined language service

For some reasons, the project could end up in an inconsistent
state where the language service is undefined. It could be that the project
is closed (?!). While we investigate this issue, put in a temporary fix
to force the project to reload.
Also note that the return type of getLanguageService() is deceiving,
because it could return undefined
https://github.com/microsoft/TypeScript/blob/1c1cd9b08d8bf1c77abb57d195cc6d79b1093390/src/server/project.ts#L797

Author: kyliau

server/src/session.ts

@@ -511,7 +511,16 @@ export class Session {
     if (!project?.languageServiceEnabled) {
       return;
     }
-
+    // TODO(kyliau): For some reasons, the project could end up in an inconsistent
+    // state where the language service is undefined. It could be that the project
+    // is closed (?!). While we investigate this issue, put in a temporary fix
+    // to force the project to reload.
+    // Also note that the return type of getLanguageService() is deceiving,
+    // because it could return undefined
+    // https://github.com/microsoft/TypeScript/blob/1c1cd9b08d8bf1c77abb57d195cc6d79b1093390/src/server/project.ts#L797
+    if (project.getLanguageService() === undefined) {
+      project.markAsDirty();
+    }
     return {
       languageService: project.getLanguageService(),
       scriptInfo,