fix(docs): update docs for SchemaField.label (#10251)

Author: hsheth2

metadata-models/src/main/pegasus/com/linkedin/schema/SchemaField.pdl

@@ -46,12 +46,15 @@ record SchemaField {
    * Label of the field. Provides a more human-readable name for the field than field path. Some sources will
    * provide this metadata but not all sources have the concept of a label. If just one string is associated with
    * a field in a source, that is most likely a description.
+   *
+   * Note that this field is deprecated and is not surfaced in the UI.
    */
   @Searchable = {
     "fieldName": "fieldLabels",
     "fieldType": "TEXT",
     "boostScore": 0.2
   }
+  @Deprecated
   label: optional string
 
   /**