chore: update eslint, enable more rules and fix their findings (#39438)

Update eslint and its plugins, enable more rules and fix their findings:

1. `unicorn/no-unsafe-string-replacement` found that uploading a file
whose name contains `$&` inserted a broken markdown link, because
`String#replace` expands such patterns in the replacement string
2. `@typescript-eslint/require-await` removes `async` from functions
that never await
3. Plugin rules not covered by a preset are now listed explicitly

---------

Co-authored-by: bircni <bircni@icloud.com>

web_src/js/utils/html.test.ts

@@ -1,6 +1,6 @@
 import {html, htmlEscape, htmlRaw} from './html.ts';
 
-test('html', async () => {
+test('html', () => {
   expect(html`<a>${'<>&\'"'}</a>`).toBe(`<a>&lt;&gt;&amp;&#39;&quot;</a>`);
   expect(html`<a>${htmlRaw('<img>')}</a>`).toBe(`<a><img></a>`);
   expect(html`<a>${htmlRaw`<img ${'&'}>`}</a>`).toBe(`<a><img &amp;></a>`);