fix(xo-server/rest-api): limit applies at the end for {backups,restore}/logs

Fixes https://xcp-ng.org/forum/post/64880

CHANGELOG.unreleased.md

@@ -11,6 +11,8 @@
 
 > Users must be able to say: “I had this issue, happy to know it's fixed”
 
+- [REST API] `limit` parameter now applies at the end of the `backups/logs` and `restore/logs` collections, i.e. it selects the last entries [Forum#64880](https://xcp-ng.org/forum/post/64880)
+
 ### Packages to release
 
 > When modifying a package, add it here with its release type.

packages/xo-server/src/xo-mixins/backups-ng-logs.mjs

@@ -209,7 +209,7 @@ export default {
             },
             'start'
           )
-    let j =
+    const j =
       before === undefined
         ? logs.length
         : sortedIndexBy(
@@ -220,11 +220,7 @@ export default {
             'start'
           )
 
-    limit += i
-    if (limit < j) {
-      j = limit
-    }
-    logs = logs.slice(i, j)
+    logs = logs.slice(Math.max(i, j - limit), j)
 
     return logs
   },