Describe the bug

Hey again :) This is similar to #7017, but dealing with items. When multiple labels are specified (i.e. the a or r param is repeated) only the last param is applied. From what I can gather, it should be possible to add/remove multiple labels at once.

It's a minor thing, but I noticed multiple i params are already supported, so ideally this could be improved to more closely align with "the spec".

To Reproduce

curl 'https://example.com/api/greader.php/reader/api/0/edit-tag'
--data-raw 'i=tag%3Agoogle.com%2C2005%3Areader%2Fitem%2F0006265cbcf0ab7c&a=user%2F-%2Flabel%2Ftestlabel1&a=user%2F-%2Flabel%2Ftestlabel2'

Expected behavior

Both labels are applied

FreshRSS version

1.24.3

Environment information

• Installation type: Docker

Additional context

No response