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

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

web_src/js/render/swagger.ts

@@ -15,7 +15,7 @@ function syncDarkModeClass(): void {
   document.documentElement.classList.toggle('dark-mode', isDark);
 }
 
-export async function initSwaggerUI(container: HTMLElement, opts: {specText: string}): Promise<void> {
+export function initSwaggerUI(container: HTMLElement, opts: {specText: string}): void {
   // swagger-ui has built-in dark mode triggered by html.dark-mode class
   syncDarkModeClass();
   window.matchMedia('(prefers-color-scheme: dark)').addEventListener('change', syncDarkModeClass);