Oredered lists increase indent bug

[Alspb]

Is there an existing issue for this?

• I have searched the existing issues

Flutter Quill version

master

Steps to reproduce

1. Select one or several ordered list items.
2. Increase their indent up to indent=5.
3. Increase their indent one more time.

Expected results

No further indent happens.

Actual results

Indent changes to indent=1 (see the video)
Increase indent bug.webm

Code sample

Code sample

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Additional Context

Screenshots / Video demonstration

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Logs

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[CatHood0]

Probably this part has a wrong verification of the indent of each current selected lines:

  void _indentSelectionEachLine(bool isIncrease) {
    final styles = document.collectAllStylesWithOffset(
      selection.start,
      selection.end - selection.start,
    );
    for (final style in styles) {
      final indent = style.value.attributes[Attribute.indent.key];
      final formatIndex = math.max(style.offset, selection.start);
      final formatLength = math.min(
            style.offset + (style.length ?? 0),
            selection.end,
          ) -
          style.offset;
      Attribute? formatAttribute;
      if (indent == null) {
        if (isIncrease) {
          formatAttribute = Attribute.indentL1;
        }
      } else if (indent.value == 1 && !isIncrease) {
        formatAttribute = Attribute.clone(Attribute.indentL1, null);
      } else if (isIncrease) {
        if (indent.value < 5) {
          formatAttribute = Attribute.getIndentLevel(indent.value + 1);
        }
      } else {
        formatAttribute = Attribute.getIndentLevel(indent.value - 1);
      }
      if (formatAttribute != null) {
        document.format(formatIndex, formatLength, formatAttribute);
      }
    }
    notifyListeners();
  }