Update dependencies on '6.4.1' in qt/qtlanguageserver

Change-Id: I723e90e0c295d7070a697bc0a5a21318b641c17e
Reviewed-by: Qt Submodule Update Bot <qt_submodule_update_bot@qt-project.org>

dependencies.yaml

 dependencies:
   ../qtbase:
-    ref: 87a8f36ff74f80b4deff062eb585009fdd4c74cf
+    ref: 905755304a474c942346774d930b92e3665c1bab
     required: true