refactor: tighten types and reuse instrument UI

src/pages/account/ui/AccountPage/position-groups.test.tsx

@@ -1,7 +1,7 @@
 import { MantineProvider } from "@mantine/core";
 import { render, screen, within } from "@testing-library/react";
 import { MemoryRouter } from "react-router";
-import { describe, expect, it } from "vitest";
+import { assert, describe, expect, it } from "vitest";
 
 import { toAccountPagePositionSections } from "../../model/positions";
 import { portfolio, position, second } from "../../model/positions.fixtures";
@@ -13,6 +13,8 @@ describe("Positions grouped by security", () => {
 			...portfolio, positions: [position, second],
 		})[0];
 
+		assert.isDefined(section);
+
 		render(
 			<MantineProvider>
 				<MemoryRouter>
@@ -27,6 +29,8 @@ describe("Positions grouped by security", () => {
 		).getAllByRole("listitem");
 
 		expect(rows).toHaveLength(2);
+		assert.isDefined(rows[0]);
+		assert.isDefined(rows[1]);
 		expect(
 			within(rows[0]).getByRole("link", { name: "Основной" }),
 		).toHaveAttribute("href", "/accounts/a");