Adds signal testing to UI elements

Extends UI element tests to include signal emission verification.

This ensures that UI elements correctly emit signals upon user interaction,
improving the reliability and responsiveness of the UI.

Adds QSignalSpy to track signal emissions for various UI components like
buttons, checkboxes, comboboxes, items, sliders, textboxes and thermos.

tests/CMakeLists.txt

@@ -1,6 +1,6 @@
 # Third Party
 find_package(GTest QUIET)
-find_package(Qt6 REQUIRED COMPONENTS Core)
+find_package(Qt6 REQUIRED COMPONENTS Core Test)
 set(CMAKE_AUTOUIC ON)
 set(CMAKE_AUTOMOC ON)
 set(CMAKE_AUTORCC ON)
@@ -23,6 +23,7 @@ if (GTest_FOUND)
         magic_enum::magic_enum
         GTest::gtest_main
         Qt::Core
+        Qt::Test
     )
 
     target_include_directories(tests