Refactor message handling and improve graphics rendering in MessageEditor

- Added SNES header include to message_data.cc for better integration.
- Simplified dictionary token formatting in ReadAllTextData function.
- Removed unused ImportMessageData function from message_data.h.
- Streamlined bitmap updates and rendering in MessageEditor, replacing instances of Renderer::GetInstance() with Renderer::Get().
- Enhanced message preview functionality with improved scrolling and drawing logic.
- Adjusted canvas sizes for better layout consistency.

src/app/editor/message/message_data.h

@@ -317,8 +317,6 @@ constexpr int kTextData2End = 0x773FF;
 // Reads all text data from the ROM and returns a vector of MessageData objects.
 void ReadAllTextData(Rom *rom, std::vector<MessageData> &list_of_texts_);
 
-std::vector<std::string> ImportMessageData(std::string_view filename);
-
 }  // namespace editor
 }  // namespace yaze