fix: correct type assignment

Author: raphael-goetz

src/flow_service/mod.rs

@@ -194,7 +194,7 @@ impl FlowUpdateService {
 
         if let Some(source) = &self.definition_source {
             for runtime_function in self.runtime_functions.iter_mut() {
-                runtime_function.definition_source = Some(source.to_string());
+                runtime_function.definition_source = source.to_string();
             }
         }