line chart shows negative y-axis, but there are no negative numbers

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**Describe the bug**
A clear and concise description of what the bug is.

**To Reproduce**
Provide us a completely reproducible code (contains the main function) in a `main.dart` file, it helps us to find the bug immediately.

**Screenshots**
If applicable, add screenshots, or videoshots to help explain your problem.

**Versions**
- which version of the Flutter are you using?
$ flutter --version
Flutter 3.19.0 • channel stable • https://github.com/flutter/flutter.git
Framework • revision bae5e49bc2 (13 days ago) • 2024-02-13 17:46:18 -0800
Engine • revision 04817c99c9
Tools • Dart 3.3.0 • DevTools 2.31.1
- which version of the FlChart are you using?
fl_chart: ^0.66.2

Start by reproducing the line-chart behavior in a main.dart file using Flutter 3.19.0 and fl_chart 0.66.2, as requested in the issue. Inspect the line-chart axis behavior with the nonnegative data shown in the screenshot. Done means the chart no longer displays a negative y-axis when its data contains no negative values.

Written by the indexing model from the issue text.