fix(design-system): use mockdate in storybook tests instead of vi [AR-46279] (#124)

## Steps to reporoduce
Navigate to [Storybook DateInput
component](https://drivenets.github.io/design-system/?path=/docs/design-system-dateinput--docs).
You'll see error: 

<img width="1554" height="734" alt="image"
src="https://github.com/user-attachments/assets/2f5e5b47-bc26-4783-a5fd-bb924a974fa8"
/>

## Root cause
In a nutshell, importing from vitest `import { vi } from 'vitest';`
breaks storybook. See details
[here](storybookjs/storybook#31400 (comment)).

## Solution
Use [mockdate](https://www.npmjs.com/package/mockdate) package to mock
dates. I took the idea from [Storybook
documentation](https://storybook.js.org/docs/writing-stories/mocking-data-and-modules/mocking-modules#setting-up-and-cleaning-up).

### Alternative Solution
I also considered
[@sinonjs/fake-timers](https://www.npmjs.com/package/@sinonjs/fake-timers)
package since it is more popular and in active development, but it's
usage looks a bit more complicated and its size is 103 kB versus 13.8 kB
of [mockdate](https://www.npmjs.com/package/mockdate)

---------

Co-authored-by: Evyatar Daud <32631382+StyleShit@users.noreply.github.com>

Author: iromanchuk-dn

packages/design-system/package.json

@@ -97,6 +97,7 @@
 		"eslint-plugin-react-hooks": "^7.0.1",
 		"eslint-plugin-storybook": "^10.2.4",
 		"jsdom": "^25.0.1",
+		"mockdate": "^3.0.5",
 		"playwright": "^1.58.1",
 		"postcss": "^8.5.6",
 		"postcss-modules": "^6.0.1",

packages/design-system/src/components/ds-date-input/ds-date-input.stories.tsx

@@ -1,7 +1,7 @@
 import type { Meta, StoryObj } from '@storybook/react-vite';
 import { useState } from 'react';
 import { expect, screen, userEvent, waitFor, within } from 'storybook/test';
-import { vi } from 'vitest';
+import MockDate from 'mockdate';
 import DsDateInput from './ds-date-input';
 import type { DsDateInputProps } from './ds-date-input.types';
 import styles from './ds-date-input.stories.module.scss';
@@ -17,14 +17,12 @@ const meta: Meta<typeof DsDateInput> = {
 		layout: 'centered',
 	},
 	beforeEach: () => {
-		vi.useFakeTimers({
-			// needed,
-			shouldAdvanceTime: true,
-		});
-		vi.setSystemTime(MOCK_DATE);
+		// We use mockdate here and not vi.useFakeTimers() because the latter is not compatible with Storybook.
+		// See https://github.com/storybookjs/storybook/issues/31400#issuecomment-2943382690 for more details.
+		MockDate.set(MOCK_DATE);
 
 		return () => {
-			vi.useRealTimers();
+			MockDate.reset();
 		};
 	},
 };