Removes migration stub headers superseded by codegen outputs

Drops 184 stub headers and obsolete stub tests now generated in the build tree.

qt6-after/qt6-migrated-legatus/Lts/Services/CentralEffectSimulation/ces_dtc.h

@@ -1,2 +0,0 @@
-#pragma once
-namespace CentralEffectSimulation { namespace Interface { class Dtc; class Ftc; } }

qt6-after/qt6-migrated-legatus/Lts/Services/CentralEffectSimulation/ces_ftc.h

@@ -1,2 +0,0 @@
-#pragma once
-namespace CentralEffectSimulation { namespace Interface { class Dtc; class Ftc; } }