Tracing: fix build: theme.h: No such file or directory

tracing_qmltyperegistrations.cpp:11:10: fatal error: theme.h: No such file or directory

That comes from src/libs/utils/meta_types/qt6utils_custom_metatypes.json:
    {
        "classes": [
            {
                "className": "Theme",
...
        ],
        "inputFile": "theme.h",
        "outputRevision": 68
    },

That file is probably wrong but I don't know how to fix it.

Change-Id: If05cb740b64f42eba21efffd17cf1c207c139d7e
Reviewed-by: Ulf Hermann <ulf.hermann@qt.io>

src/libs/tracing/CMakeLists.txt

@@ -105,3 +105,7 @@ qt_add_qml_module(Tracing
   SOURCES
     ${TRACING_CPP_SOURCES}
 )
+extend_qtc_library(Tracing
+  INCLUDES
+    ../utils/theme
+)