Fix for auto scroll issue

[starfreck]

closes: https://github.com/Fintasys/emoji_picker_flutter/issues/179

Usage Example:

Create a new ScrollController and pass it to TextField and EmojiPicker :

final scrollController = ScrollController();
...
TextField(
    minLines: 1,
    maxLines: 4, // Auto scrolling should work after 4th line
    focusNode: focusNode,
    controller: textEditingController,
    scrollController: scrollController,
    decoration: const InputDecoration(
        hintText: "Message",
        border: InputBorder.none,
    ),
),
...
EmojiPicker(
    textEditingController: textEditingController,
    scrollController: scrollController,
    onBackspacePressed: () {},
    ....
    ),
),

Reference: https://stackoverflow.com/questions/71408717/flutter-textfield-content-does-not-scroll-automatically-when-inserting-text