%pip install magic with inline comment causes InvalidRequirement error

## Description

When using JupyterLite, adding an inline comment to a %pip install line e.g.:

`%pip install seaborn # comment`

the comment is interpreted as part of the package list, resulting in an `InvalidRequirement` error.

The behavior appears inconsistently across browsers — for example, it fails in Brave (Chromium-based) but not in Chrome.

## Reproduce

1. Launch a JupyterLite notebook (e.g., from https://jupyterlite.github.io/demo).

2. In a code cell, enter the following line:
`%pip install seaborn # required to use seaborn in jupyterlite`

3. Run the cell.

## Expected behavior

The magic command parser strips the inline comments before passing the arguments to piplite, in this case resulting in seaborn being installed no matter the browser.

## Context

- JupyterLite version: latest (from https://jupyterlite.github.io/demo as of 03-07-2025)
- Operating System and version: Ubuntu 24.04.2 LTS
- Browser and version: Firefox 139.0.4 (64-bit)

Browser Output

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