Do not add a fallback field reference if front side contains conditionals (#2859)

* Do not add a fallback field ref if front contains conditionals

* Ensure field reference when there are only conditionals

rslib/src/template.rs

@@ -741,9 +741,9 @@ impl ParsedTemplate {
     }
 
     pub(crate) fn contains_field_replacement(&self) -> bool {
-        self.0
-            .iter()
-            .any(|node| matches!(node, ParsedNode::Replacement { key: _, filters: _ }))
+        let mut set = HashSet::new();
+        find_field_references(&self.0, &mut set, false, false);
+        !set.is_empty()
     }
 
     pub(crate) fn add_missing_field_replacement(&mut self, field_name: &str, is_cloze: bool) {