Fix terminal freezing self and whole app when internet is disconnected (#5870)

- Remove uses to navigator.onLine as not needed and because that value
  cannot be trusted (see several bug reports on chromium)

- Fix infinite loop when socket is not connected in flush

- Add some simple tests

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

src/renderer/api/__tests__/websocket-api.test.ts

@@ -0,0 +1,37 @@
+/**
+ * Copyright (c) OpenLens Authors. All rights reserved.
+ * Licensed under MIT License. See LICENSE in root directory for more information.
+ */
+
+import type { WebSocketEvents } from "../websocket-api";
+import { WebSocketApi } from "../websocket-api";
+
+class TestWebSocketApi extends WebSocketApi<WebSocketEvents> {
+  flush(): void {
+    super.flush();
+  }
+}
+
+describe("WebsocketApi tests", () => {
+  let api: TestWebSocketApi;
+
+  beforeEach(() => {
+    api = new TestWebSocketApi({});
+  });
+
+  describe("before connection", () => {
+    it("does not hang when flush is called", () => {
+      api.flush();
+    });
+
+    describe("when a message has been sent", () => {
+      beforeEach(() => {
+        api.send("a command");
+      });
+
+      it("does not hang when flush is called", () => {
+        api.flush();
+      });
+    });
+  });
+});