initialize page layout with lowercase letters (fixes #1136)

nicegui/client.py

@@ -35,7 +35,7 @@ class Client:
         self.environ: Optional[Dict[str, Any]] = None
         self.shared = shared
 
-        with Element('q-layout', _client=self).props('view="HHH LpR FFF"').classes('nicegui-layout') as self.layout:
+        with Element('q-layout', _client=self).props('view="hhh lpr fff"').classes('nicegui-layout') as self.layout:
             with Element('q-page-container') as self.page_container:
                 with Element('q-page'):
                     self.content = Element('div').classes('nicegui-content')