website/js: fix htmx sse extension (again)

The fix we're after was in this file, but it depended on some htmx 2.0
API, which isn't released yet. This patches the part that uses the new
API to use the old version instead. We can upgrade later to the proper
version

assets/js/htmx-sse.js

@@ -269,7 +269,23 @@ This extension adds support for Server Sent Events to htmx.  See /www/extensions
 
         var swapSpec = api.getSwapSpecification(elt)
         var target = api.getTarget(elt)
-        api.swap(target, content, swapSpec)
+        var settleInfo = api.makeSettleInfo(elt)
+
+        api.selectAndSwap(swapSpec.swapStyle, target, elt, content, settleInfo)
+
+        settleInfo.elts.forEach(function (elt) {
+            if (elt.classList) {
+                elt.classList.add(htmx.config.settlingClass)
+            }
+            api.triggerEvent(elt, 'htmx:beforeSettle')
+        })
+
+        // Handle settle tasks (with delay if requested)
+        if (swapSpec.settleDelay > 0) {
+            setTimeout(doSettle(settleInfo), swapSpec.settleDelay)
+        } else {
+            doSettle(settleInfo)()
+        }
     }
 
     /**