fix: encodes upload filename urls (#10048)

### What?

Previously, upload files urls were not being encoded.

### Why?

As a result, this could lead to discrepancies where upload filenames
with spaces - the spaces would not be encoded as %20 in the URL.

### How?

To address this issue, we simply need to encode the filename of the
upload media.

Fixes #9698

packages/payload/src/uploads/getBaseFields.ts

@@ -12,7 +12,7 @@ type GenerateURLArgs = {
 }
 const generateURL = ({ collectionSlug, config, filename }: GenerateURLArgs) => {
   if (filename) {
-    return `${config.serverURL || ''}${config.routes.api || ''}/${collectionSlug}/file/${filename}`
+    return `${config.serverURL || ''}${config.routes.api || ''}/${collectionSlug}/file/${encodeURIComponent(filename)}`
   }
   return undefined
 }