Add report room dialog button/dialog. (#29513)

* Add report room dialog button/dialog.

* Update copy

* fixup tests / lint

* Fix title in test.

* update snapshot

* Add unit tests for dialog

* lint

test/unit-tests/components/views/dialogs/ReportRoomDialog-test.tsx

@@ -0,0 +1,66 @@
+/*
+Copyright 2025 New Vector Ltd.
+
+SPDX-License-Identifier: AGPL-3.0-only OR GPL-3.0-only OR LicenseRef-Element-Commercial
+Please see LICENSE files in the repository root for full details.
+*/
+
+import { render } from "jest-matrix-react";
+import userEvent from "@testing-library/user-event";
+import React from "react";
+
+import { ReportRoomDialog } from "../../../../../src/components/views/dialogs/ReportRoomDialog";
+import SdkConfig from "../../../../../src/SdkConfig";
+import { stubClient } from "../../../../test-utils";
+
+const ROOM_ID = "!foo:bar";
+
+describe("ReportRoomDialog", () => {
+    const onFinished: jest.Mock<any, any> = jest.fn();
+    const reportRoom: jest.Mock<any, any> = jest.fn();
+    beforeEach(() => {
+        jest.resetAllMocks();
+        const client = stubClient();
+        client.reportRoom = reportRoom;
+
+        SdkConfig.put({
+            report_event: {
+                admin_message_md: `
+# You should know
+
+This doesn't actually go **anywhere**.`,
+            },
+        });
+    });
+
+    afterEach(() => {
+        SdkConfig.reset();
+    });
+
+    it("can close the dialog", async () => {
+        const { getByTestId } = render(<ReportRoomDialog roomId={ROOM_ID} onFinished={onFinished} />);
+        await userEvent.click(getByTestId("dialog-cancel-button"));
+        expect(onFinished).toHaveBeenCalledWith(false);
+    });
+
+    it("displays admin message", async () => {
+        const { container } = render(<ReportRoomDialog roomId={ROOM_ID} onFinished={onFinished} />);
+        expect(container).toMatchSnapshot();
+    });
+
+    it("can submit a report", async () => {
+        const REASON = "This room is bad!";
+        const { getByLabelText, getByText, getByRole } = render(
+            <ReportRoomDialog roomId={ROOM_ID} onFinished={onFinished} />,
+        );
+
+        await userEvent.type(getByLabelText("Reason"), REASON);
+        await userEvent.click(getByRole("button", { name: "Send report" }));
+
+        expect(reportRoom).toHaveBeenCalledWith(ROOM_ID, REASON);
+        expect(getByText("Your report was sent.")).toBeInTheDocument();
+
+        await userEvent.click(getByRole("button", { name: "Close dialog" }));
+        expect(onFinished).toHaveBeenCalledWith(true);
+    });
+});