introduce _set_props in analogy to _text_to_model_text in TextElement

nicegui/elements/mixins/source_element.py

@@ -16,7 +16,7 @@ class SourceElement(Element):
     def __init__(self, *, source: Union[str, Path], **kwargs: Any) -> None:
         super().__init__(**kwargs)
         self.source = source
-        self._handle_source_change(source)
+        self._set_props(source)
 
     def bind_source_to(self,
                        target_object: Any,
@@ -80,7 +80,10 @@ class SourceElement(Element):
 
         :param source: The new source.
         """
+        self._set_props(source)
+        self.update()
+
+    def _set_props(self, source: str) -> None:
         if is_file(source):
             source = core.app.add_static_file(local_file=source)
         self._props['src'] = source
-        self.update()