Not able to change wave amplitude in runtime

**Describe the bug**
Changes of `waveAmplitude` doesn't make any affects.

**To Reproduce**
Steps to reproduce the behavior:
1. Pass some `waveAmplitude` to the `WaveWidget`.
2. Change `waveAmplitude` in runtime.

**Expected behavior**
The changes applied to the waves.

**Additional context**
Happens in all platforms.
