docs(link): update upload form by url support doc link DEV-1349 (#6506)

### 📣 Summary

Updated the XLSForm import help link to point to the correct support
article section with anchor.

### 👀 Preview steps
1. ℹ️ have an account
2. Navigate to create a new project
3. Select "Import XLSForm via URL" option
4. 🔴 [on main] notice the help link points to `xls_url.html` (broken)
5. 🟢 [on PR] notice the help link points to
`xlsform_with_kobotoolbox.html#importing-an-xlsform-via-url`
6. Click the help link
7. 🟢 notice it takes you to the correct section of the support
documentation

Author: pauloamorimbr

jsapp/js/components/modalForms/projectSettings.js

@@ -31,7 +31,7 @@ import sessionStore from '#/stores/session'
 import { addRequiredToLabel } from '#/textUtils'
 import { escapeHtml, isAValidUrl, join, notify, validFileTypes } from '#/utils'
 
-const VIA_URL_SUPPORT_URL = 'xls_url.html'
+const VIA_URL_SUPPORT_URL = 'xlsform_with_kobotoolbox.html#importing-an-xlsform-via-url'
 
 /**
  * This is used for multiple different purposes: