GPv3: Include other channel selection modes

Support extend and extend range channel selection.
Some channeltype don't have active channel and they don't support
`extend range`. This is checked with the help of `ANIM_is_active_channel`.
Add switch case for new GPv3 channels in above funnction to detect
active channels and support `extend range`

@@ -355,1 +355,4 @@
     }
+    case ANIMTYPE_GREASE_PENCIL_LAYER: {
+      GreasePencil *grease_pencil = reinterpret_cast<GreasePencil *>(ale->id);
+      return grease_pencil->active_layer == ale->data;

@@ -3636,4 +3640,3 @@
                                                     const int /*filter*/)
 {
-  /* TODO: Implement other selection modes. */
   GreasePencilLayer *layer = static_cast<GreasePencilLayer *>(ale->data);

@@ -3645,2 +3657,2 @@
-  layer->base.flag |= GP_LAYER_TREE_NODE_SELECT;
-  grease_pencil->active_layer = layer;
+  /* Active channel is not changed during range select. */
+  if (selectmode != SELECT_EXTEND_RANGE) {

@@ -3646,1 +3657,3 @@
-  grease_pencil->active_layer = layer;
+  /* Active channel is not changed during range select. */
+  if (selectmode != SELECT_EXTEND_RANGE) {
+    grease_pencil->active_layer = layer;