feat: add legend for active overlays

Closes MIN-196

Objective

Display list of overlays legends along with theirs names in the overlays drawer

What has been done:

• implementation of overlays legends in the overlays drawer
• unit tests

src/components/Map/Drawer/OverlaysDrawer/OverlaysLegends/OverlaySingleLegend/OverlaySingleLegend.component.test.tsx

+import { BASE_API_URL, PROJECT_ID } from '@/constants';
+import { overlayFixture } from '@/models/fixtures/overlaysFixture';
+import { MapOverlay } from '@/types/models';
+import { render, screen } from '@testing-library/react';
+import { OverlaySingleLegend } from './OverlaySingleLegend.component';
+
+const renderComponent = ({ overlay }: { overlay: MapOverlay }): void => {
+  render(<OverlaySingleLegend overlay={overlay} />);
+};
+
+describe('OverlaySingleLegend - component', () => {
+  beforeEach(() => {
+    renderComponent({
+      overlay: {
+        ...overlayFixture,
+        name: 'overlay name',
+        idObject: 1234,
+      },
+    });
+  });
+
+  it('should render title with overlay name', () => {
+    expect(screen.getByText('overlay name')).toBeInTheDocument();
+  });
+
+  it('should render image with valid src and alt', () => {
+    const image = screen.getByAltText('overlay name legend');
+
+    expect(image).toBeInTheDocument();
+    expect(image.getAttribute('src')).toBe(
+      `${BASE_API_URL}/projects/${PROJECT_ID}/overlays/1234:downloadLegend`,
+    );
+  });
+});