FIX: fix for 203

https://gitlab.com/caosdb/caosdb-server/-/issues/203

src/main/java/org/caosdb/server/query/CQLParser.g4

@@ -133,6 +133,7 @@ entity_filter returns [EntityFilterInterface filter]
     (
         (
             LPAREN WHITE_SPACE?
+            (HAS_A (PROPERTY)?)?
             (
                 filter_expression {$filter = $filter_expression.efi;}
                 | conjunction {$filter = $conjunction.c;}
@@ -433,6 +434,7 @@ conjunction returns [Conjunction c]
         f1 = filter_expression {$c.add($f1.efi);}
         |
         LPAREN WHITE_SPACE?
+        (HAS_A (PROPERTY)?)?
         (
             f4 = filter_expression {$c.add($f4.efi);}
             | disjunction {$c.add($disjunction.d);}
@@ -473,6 +475,7 @@ disjunction returns [Disjunction d]
         f1 = filter_expression {$d.add($f1.efi);}
         |
         LPAREN WHITE_SPACE?
+        (HAS_A (PROPERTY)?)?
         (
             f4 = filter_expression {$d.add($f4.efi);}
             | conjunction {$d.add($conjunction.c);}