[BUG] Render emojis in labels in issue info popup

- Currently emojis that are part of the label's name aren't rendered
when shown in the popup that you get when you hover over issue
references.
- This patch fixes that by rendering the emoji.
- Adds CSS to not make the emoji big in the label.
- Resolves #1531

web_src/js/components/ContextPopup.test.js

@@ -0,0 +1,39 @@
+import {mount, flushPromises} from '@vue/test-utils';
+import ContextPopup from './ContextPopup.vue';
+
+test('renders a issue info popup', async () => {
+  const owner = 'user2';
+  const repo = 'repo1';
+  const index = 1;
+  vi.spyOn(global, 'fetch').mockResolvedValue({
+    json: vi.fn().mockResolvedValue({
+      ok: true,
+      created_at: '2023-09-30T19:00:00Z',
+      repository: {full_name: owner},
+      pull_request: null,
+      state: 'open',
+      title: 'Normal issue',
+      body: 'Lorem ipsum...',
+      number: index,
+      labels: [{color: 'ee0701', name: "Bug :+1: <script class='evil'>alert('Oh no!');</script>"}],
+    }),
+    ok: true,
+  });
+
+  const wrapper = mount(ContextPopup);
+  wrapper.vm.$el.dispatchEvent(new CustomEvent('ce-load-context-popup', {detail: {owner, repo, index}}));
+  await flushPromises();
+
+  // Header
+  expect(wrapper.get('p:nth-of-type(1)').text()).toEqual('user2 on Sep 30, 2023');
+  // Title
+  expect(wrapper.get('p:nth-of-type(2)').text()).toEqual('Normal issue #1');
+  // Body
+  expect(wrapper.get('p:nth-of-type(3)').text()).toEqual('Lorem ipsum...');
+  // Check that the state is correct.
+  expect(wrapper.get('svg').classes()).toContain('octicon-issue-opened');
+  // Ensure that script is not an element.
+  expect(() => wrapper.get('.evil')).toThrowError();
+  // Check content of label
+  expect(wrapper.get('.ui.label').text()).toContain("Bug 👍 <script class='evil'>alert('Oh no!');</script>");
+});