fix image insert

[cristianoccazinsp]

On iOS, if your html is empty and you call insertImage, it does nothing but adding an empty
tag.

With this PR, we add an artificial break line after the image is inserted so the above is fixed.

[stulip]

Image Insert is not a must

[nick-mccomb-easygo]

Focus the RichEditor before inserting the image
editorRef.current?.focusContentEditor();
then
editorRef.current?.insertImage(...