Nodes: Lower main socket priority of menu sockets

This patch lowers the priority of menu sockets from the maximum priority
to the lowest priority. That's because menu sockets are nearly never the
main socket.

The current state is blocking the adoption of menu sockets in the
compositor, since most of the compositor nodes have color and float main
sockets, which currently have lower priority than menu sockets, making
node link insertion fail.

Pull Request: https://projects.blender.org/blender/blender/pulls/144779

source/blender/editors/space_node/node_relationships.cc

@@ -2604,16 +2604,18 @@ static int get_main_socket_priority(const bNodeSocket *socket)
   switch (eNodeSocketDatatype(socket->type)) {
     case SOCK_CUSTOM:
       return 0;
-    case SOCK_BOOLEAN:
+    case SOCK_MENU:
       return 1;
-    case SOCK_INT:
+    case SOCK_BOOLEAN:
       return 2;
-    case SOCK_FLOAT:
+    case SOCK_INT:
       return 3;
-    case SOCK_VECTOR:
+    case SOCK_FLOAT:
       return 4;
-    case SOCK_RGBA:
+    case SOCK_VECTOR:
       return 5;
+    case SOCK_RGBA:
+      return 6;
     case SOCK_STRING:
     case SOCK_SHADER:
     case SOCK_OBJECT:
@@ -2624,10 +2626,9 @@ static int get_main_socket_priority(const bNodeSocket *socket)
     case SOCK_COLLECTION:
     case SOCK_TEXTURE:
     case SOCK_MATERIAL:
-    case SOCK_MENU:
     case SOCK_BUNDLE:
     case SOCK_CLOSURE:
-      return 6;
+      return 7;
   }
   return -1;
 }