feat(website): Increase max acceptable URL length to 7400 (#6488)

This makes it possible to get a URL to copy for downloading when all
columns are enabled for download, which seems quite important.

<img width="894" height="718" alt="image"
src="https://github.com/user-attachments/assets/ab5ecce7-70d0-4d50-8d27-709efa4a312d"
/>


It is recommended that all servers be able to support up to 8k URLs.
Below from Claude

___

# Maximum URL Lengths by System

A reference guide to URL length limits across browsers, servers, and
other systems.

## Browsers

| Browser | Max URL Length |
|---------|---------------|
| Internet Explorer | 2,083 characters |
| Microsoft Edge | 2,083 characters (legacy), ~80,000+ (Chromium-based)
|
| Google Chrome | ~32,779 characters (address bar), 2 MB (internally) |
| Mozilla Firefox | ~65,536 characters (address bar may truncate display
~64k) |
| Safari | ~80,000 characters |
| Opera | ~190,000 characters |

## Web Servers

| Server | Default Max URL Length |
|--------|----------------------|
| Apache HTTP Server | 8,177 characters (`LimitRequestLine` directive,
default 8190 bytes for full request line) |
| Nginx | 4,096 or 8,192 characters (depends on
`large_client_header_buffers`) |
| Microsoft IIS | 16,384 characters (configurable via `maxUrl`) |
| Tomcat | 8,192 characters (configurable via `maxHttpHeaderSize`) |
| Node.js (HTTP) | 8,192 characters (default `--max-http-header-size`) |

🚀 Preview: https://increasemax.loculus.org

Author: theosanderson

website/src/routes/routes.ts

@@ -10,7 +10,7 @@ export type ContinueSubmissionIntent = {
     organism: string;
 };
 
-export const approxMaxAcceptableUrlLength = 1900;
+export const approxMaxAcceptableUrlLength = 7400;
 
 export const routes = {
     apiDocumentationPage: () => '/api-documentation',