0.3.0 does not depend on `jupyterlite-core`

## Description

This does not have PEP 621 dependencies on `jupyterlite-javascript-kernel`

## Reproduce

Given:
```yaml
# environment.yml
channels: [conda-forge]
dependencies:
- python
- pip
- pip:
- jupyterlite-javascript-kernel
```

Then
```bash
mamba upgrade --file environment.yml --prefix .venv
source activate .venv
pip list | grep jupyter
```
See:
```
jupyterlite_javascript_kernel 0.3.0
```

## Expected behavior

```
jupyter_core x.x.x
jupyterlite-core 0.3.0
jupyterlite_javascript_kernel 0.3.0
```

## Context

- https://github.com/conda-forge/jupyterlite-core-feedstock/issues/22
- https://github.com/conda-forge/staged-recipes/pull/26440

首先使用 issue 中引用的 PEP 621 元数据处理依赖声明，然后使用提供的 mamba 和 pip 命令重现 environment.yml 的安装过程。安装 jupyterlite-javascript-kernel 0.3.0 时也安装 jupyterlite-core 0.3.0，并与预期的软件包列表一致，即表示完成。

由索引模型根据 Issue 内容生成。