Assets: Enable collection assets (no longer experimental)

With automatic collection previews (810e225c26) and a toggle for
collection instancing (previous commit) supported, there are no known
blocking issues for collection assets. There are still further
improvements to come as part of regular developemt (e.g. bounding box
based snapping).

source/blender/editors/asset/ED_asset_type.h

@@ -16,7 +16,7 @@ struct ID;
 
 bool ED_asset_type_id_is_non_experimental(const struct ID *id);
 #define ED_ASSET_TYPE_IDS_NON_EXPERIMENTAL_FLAGS \
-  (FILTER_ID_MA | FILTER_ID_OB | FILTER_ID_AC | FILTER_ID_WO | FILTER_ID_NT)
+  (FILTER_ID_MA | FILTER_ID_GR | FILTER_ID_OB | FILTER_ID_AC | FILTER_ID_WO | FILTER_ID_NT)
 
 /**
  * Check if the asset type for \a id (which doesn't need to be an asset right now) can be an asset,
@@ -39,7 +39,7 @@ int64_t ED_asset_types_supported_as_filter_flags(void);
  * Should start with a consonant, so usages can prefix it with "a" (not "an").
  */
 #define ED_ASSET_TYPE_IDS_NON_EXPERIMENTAL_UI_STRING \
-  "Material, Object, Pose Action, Node Group or World"
+  "Material, Collection, Object, Pose Action, Node Group or World"
 
 #ifdef __cplusplus
 }

source/blender/editors/asset/intern/asset_type.cc

@@ -16,7 +16,7 @@ bool ED_asset_type_id_is_non_experimental(const ID *id)
 {
   /* Remember to update #ED_ASSET_TYPE_IDS_NON_EXPERIMENTAL_UI_STRING and
    * #ED_ASSET_TYPE_IDS_NON_EXPERIMENTAL_FLAGS() with this! */
-  return ELEM(GS(id->name), ID_MA, ID_OB, ID_AC, ID_WO, ID_NT);
+  return ELEM(GS(id->name), ID_MA, ID_GR, ID_OB, ID_AC, ID_WO, ID_NT);
 }
 
 bool ED_asset_type_is_supported(const ID *id)