Describe the bug

When I create a dynamic OPML, the category will not populate with feeds.

In my specific scenario, I'm generating and hosting an OPML on a local NIGNX server, but I was able to replicate the problem using the same OPML used in #5727

Log wise, this seemed to be all related to the issue:

POST /i/?c=category&a=refreshOpml&id=19 HTTP/1.1" 302 - "-" "Mozilla/5.0 (X11; Linux x86_64; rv:133.0) Gecko/20100101 Firefox/133.0
FreshRSS[35]: FreshRSS GET opml https://www.byjp.me/reading-lists/curiosity/feeds.opml 

To Reproduce

1. Go to subscription management

2. "Add a feed or category"

3. Go to "Add dynamic OPML"
   a. Give the category any name (e.g. "test')
   b. For the URL you can use https://www.byjp.me/reading-lists/curiosity/feeds.opml I found from another issue as a an example
   

4. View the category in subscription management and see that it is empty
   

Expected behavior

I'm expecting that the category with populate with the feeds specified in the remote OPML file.

FreshRSS version

1.26.0

System information

• Database version: sqlite 3.40.1
• PHP version: 8.2.26
• Installation type: Docker freshrss/freshrss:1.26.0
• Web server type: Apache/2.4.62 (Debian)
• Device: Laptop
• Client OS: Fedora 41 (Workstation Edition)
• Browser: Mozilla/5.0 (X11; Linux x86_64; rv:133.0) Gecko/20100101 Firefox/133.0

Additional context

No response