fix(core): fetch correct source and target nodes for isValidConnection (#1922)

* fix(core): fetch correct source and target nodes for isValidConnection

Signed-off-by: braks <78412429+bcakmakoglu@users.noreply.github.com>

* chore(changeset): add

---------

Signed-off-by: braks <78412429+bcakmakoglu@users.noreply.github.com>

.changeset/stale-phones-cross.md

@@ -0,0 +1,5 @@
+---
+"@vue-flow/core": patch
+---
+
+Fetch the correct source and target nodes for isValidConnection.

packages/core/src/utils/handle.ts

@@ -191,8 +191,8 @@ export function isValidHandle(
       isValidConnection(connection, {
         nodes,
         edges,
-        sourceNode: findNode(fromNodeId)!,
+        sourceNode: findNode(connection.source)!,
-        targetNode: findNode(handleNodeId)!,
+        targetNode: findNode(connection.target)!,
       })
 
     result.toHandle = handle