qt, build: remove unneeded Q_IMPORT_PLUGIN macro calls

After the recent full removal of Autotools (PR #30664), these
macros are not needed anymore in the .cpp files according to the
TODO in qt's CMakeLists.txt. Tested building on OpenBSD 7.5, where
the XCB plugin was still imported according to the debug log.

src/qt/CMakeLists.txt

@@ -13,9 +13,6 @@ endif()
 
 get_target_property(qt_lib_type Qt5::Core TYPE)
 
-# TODO: After the transition from Autotools to CMake,
-# all `Q_IMPORT_PLUGIN` macros can be deleted from the
-# qt/bitcoin.cpp and qt/test/test_main.cpp source files.
 function(import_plugins target)
  if(qt_lib_type STREQUAL "STATIC_LIBRARY")
  set(plugins Qt5::QMinimalIntegrationPlugin)

src/qt/bitcoin.cpp

@@ -60,21 +60,6 @@
 #include <QTranslator>
 #include <QWindow>
 
-#if defined(QT_STATIC)
-#include <QtPlugin>
-#if defined(QT_QPA_PLATFORM_XCB)
-Q_IMPORT_PLUGIN(QXcbIntegrationPlugin);
-#elif defined(QT_QPA_PLATFORM_WINDOWS)
-Q_IMPORT_PLUGIN(QWindowsIntegrationPlugin);
-Q_IMPORT_PLUGIN(QWindowsVistaStylePlugin);
-#elif defined(QT_QPA_PLATFORM_COCOA)
-Q_IMPORT_PLUGIN(QCocoaIntegrationPlugin);
-Q_IMPORT_PLUGIN(QMacStylePlugin);
-#elif defined(QT_QPA_PLATFORM_ANDROID)
-Q_IMPORT_PLUGIN(QAndroidPlatformIntegrationPlugin)
-#endif
-#endif
-
 // Declare meta types used for QMetaObject::invokeMethod
 Q_DECLARE_METATYPE(bool*)
 Q_DECLARE_METATYPE(CAmount)

src/qt/test/test_main.cpp

@@ -28,22 +28,6 @@
 
 #include <functional>
 
-#if defined(QT_STATIC)
-#include <QtPlugin>
-#if defined(QT_QPA_PLATFORM_MINIMAL)
-Q_IMPORT_PLUGIN(QMinimalIntegrationPlugin);
-#endif
-#if defined(QT_QPA_PLATFORM_XCB)
-Q_IMPORT_PLUGIN(QXcbIntegrationPlugin);
-#elif defined(QT_QPA_PLATFORM_WINDOWS)
-Q_IMPORT_PLUGIN(QWindowsIntegrationPlugin);
-#elif defined(QT_QPA_PLATFORM_COCOA)
-Q_IMPORT_PLUGIN(QCocoaIntegrationPlugin);
-#elif defined(QT_QPA_PLATFORM_ANDROID)
-Q_IMPORT_PLUGIN(QAndroidPlatformIntegrationPlugin)
-#endif
-#endif
-
 const std::function<void(const std::string&)> G_TEST_LOG_FUN{};
 
 const std::function<std::vector<const char*>()> G_TEST_COMMAND_LINE_ARGUMENTS{};