ColorizeAnimatedText() stumbles on the first letter

**Describe the bug**
In the Colorize animation, the animation stumbles on the first letter, and only then goes through the whole word.
I checked it on different simulators and on a real Android device, it is displayed the same everywhere.

**To Reproduce**
Steps to reproduce the behavior:
1. Use `ColorizeAnimatedText()` anywhere. It gives the same behavior all the time.

**Expected behavior**
Just like how it is in https://pub.dev/packages/animated_text_kit#colorize

**Screenshots**
[![enter image description here][1]][1]

**Flutter:**
- version 2.2.3
- channel stable

**Dart:**
- version 2.13.4

**Additional context**
My code:

```dart
Padding(
padding: EdgeInsets.only(top: 10),
child: AnimatedTextKit(
animatedTexts: [
ColorizeAnimatedText(
"Test Text",
colors: colorizeColors,
textStyle: GoogleFonts.inconsolata(fontSize: 27),
),
],
pause: Duration(milliseconds: 0),
isRepeatingAnimation: true,
repeatForever: true,
)
),
```

[1]: https://i.stack.imgur.com/WLXbN.gif

Look at the ColorizeAnimatedText implementation in the animated_text_kit package, likely in lib/src/colorize.dart. Reproduce the bug using the provided code snippet. The issue mentions the animation stumbles on the first letter; examine the animation loop and initial state setup. Check for existing tests in the test/ directory related to ColorizeAnimatedText. The goal is to make the animation start smoothly as shown in the package documentation.

索引モデルが issue の本文から書いたものです。