no Fields.ofAll

Author: wu-hui

google-cloud-firestore/src/main/java/com/google/cloud/firestore/pipeline/expressions/Field.java

@@ -25,11 +25,6 @@ public static Field of(String path) {
     return new Field(FieldPath.fromDotSeparatedString(path));
   }
 
-  @BetaApi
-  public static Field ofAll() {
-    return new Field(FieldPath.of(""));
-  }
-
   @InternalApi
   public Value toProto() {
     return Value.newBuilder().setFieldReferenceValue(path.toString()).build();