[ADF-3435][ADF-3436] fix schema json (#3688)

* fix schema json

* fix description

* update search config from documentation

docs/content-services/search-filter.component.md

@@ -61,12 +61,15 @@ A typical configuration is shown below:
             { "query": "TYPE:'cm:folder' OR TYPE:'cm:content'" },
             { "query": "NOT cm:creator:System" }
         ],
-        "facetFields": [
+        "facetFields": {
+          "expanded": true,
+          "fields": [
             { "field": "content.mimetype", "mincount": 1, "label": "Type" },
             { "field": "content.size", "mincount": 1, "label": "Size" },
             { "field": "creator", "mincount": 1, "label": "Creator" },
             { "field": "modifier", "mincount": 1, "label": "Modifier" }
-        ],
+          ]
+        },
         "facetQueries": {
             "label": "My facet queries",
             "pageSize": 4,

lib/core/app-config/schema.json

@@ -568,6 +568,15 @@
               }
             },
             "facetFields": {
+              "type": "object",
+              "required": ["fields"],
+              "properties": {
+                "expanded": {
+                  "description": "Toggles expanded state of the facet field",
+                  "type": "boolean"
+                },
+                "fields": {
+                  "description": "List of custom facet fields",
                   "type": "array",
                   "minItems": 1,
                   "items": {
@@ -601,6 +610,8 @@
                       "offset": { "type": "integer" }
                     }
                   }
+                }
+              }
             },
             "facetQueries": {
               "type": "object",