add not logged in warning to flags modal, refactored to its own lit component (#3521)

## Description:

So players know they are logged out and don't think their purchased
flags dissappeared.

## Please complete the following:

- [x] I have added screenshots for all UI updates
- [x] I process any text displayed to the user through translateText()
and I've added it to the en.json file
- [x] I have added relevant tests to the test directory
- [x] I confirm I have thoroughly tested these changes and take full
responsibility for any bugs introduced

## Please put your Discord username so you can be contacted if a bug or
regression is found:

evan

src/client/FlagInputModal.ts

@@ -9,6 +9,7 @@ import { fetchCosmetics, flagRelationship } from "./Cosmetics";
 import { translateText } from "./Utils";
 import { BaseModal } from "./components/BaseModal";
 import "./components/FlagButton";
+import "./components/NotLoggedInWarning";
 import { modalHeader } from "./components/ui/ModalHeader";
 
 @customElement("flag-input-modal")
@@ -103,6 +104,7 @@ export class FlagInputModal extends BaseModal {
             title: translateText("flag_input.title"),
             onBack: () => this.close(),
             ariaLabel: translateText("common.back"),
+            rightContent: html`<not-logged-in-warning></not-logged-in-warning>`,
           })}
 
           <div class="md:flex items-center gap-2 justify-center mt-4">