Backends: SDL2/SDL3: Fixed bad merge in docking branch (#6735)

backends/imgui_impl_sdl2.cpp

@@ -548,7 +548,7 @@ bool ImGui_ImplSDL2_InitForSDLRenderer(SDL_Window* window, SDL_Renderer* rendere
 
 bool ImGui_ImplSDL2_InitForOther(SDL_Window* window)
 {
-    return ImGui_ImplSDL2_Init(window, nullptr);
+    return ImGui_ImplSDL2_Init(window, nullptr, nullptr);
 }
 
 void ImGui_ImplSDL2_Shutdown()

backends/imgui_impl_sdl3.cpp

@@ -475,7 +475,7 @@ bool ImGui_ImplSDL3_InitForSDLRenderer(SDL_Window* window, SDL_Renderer* rendere
 
 bool ImGui_ImplSDL3_InitForOther(SDL_Window* window)
 {
-    return ImGui_ImplSDL3_Init(window, nullptr);
+    return ImGui_ImplSDL3_Init(window, nullptr, nullptr);
 }
 
 void ImGui_ImplSDL3_Shutdown()