Warn on invalid JSON file (#1159)

* add error dialog

* show error modal on file dnd

* add locales

* Update src/locales/en.json

Co-Authored-By: Lipis <lipiridis@gmail.com>

* Update src/data/blob.ts

* Update src/data/blob.ts

* fix titles, update snapshots

* make modal smaller

* fix dnd wrong file type

* reset errorMessage

Co-authored-by: Faustino Kialungila <faustino.kialungila@gmail.com>
Co-authored-by: Lipis <lipiridis@gmail.com>

src/types.ts

@@ -11,6 +11,7 @@ export type Point = Readonly<RoughPoint>;
 
 export type AppState = {
   isLoading: boolean;
+  errorMessage: string | null;
   draggingElement: ExcalidrawElement | null;
   resizingElement: ExcalidrawElement | null;
   multiElement: ExcalidrawLinearElement | null;