Tests in Distribution Files

還沒有人認領這個 Issue。

This may be a stupid question, but I don't see the reason why this is the case.

I was running the following (essentially checking out matplotlib in a venv)
```bash
uv init example
cd example
uv add matplotlib
```
This created a new repo with a virtual environment.
When I was checking out `example/.venv/lib/python3.13/site-packages/matplotlib` I found the `tests` directory with a bunch of `pytest` files.
Basically, [these files](https://github.com/matplotlib/matplotlib/tree/main/lib/matplotlib/tests) seem to be distributed.
I then ran `du -h` and found out that the tests alone amass to just about `2MB`.
This seems to be a lot of wasted disk space.

Therefore, my questions.
- Are these tests actually used in the distributed package?
- Would it make sense to exclude them from the distribution, if they are not used by any user anyway?

先檢查 lib/matplotlib/tests，以及產生透過 uv 安裝的 matplotlib 發行版的套件封裝設定。確認分發的測試是否為任何受支援的工作流程所需，並測量產生的套件內容。完成的條件是已有記錄在文件中的答案，且在適當情況下，已有獲同意的套件封裝變更，並驗證已安裝的套件仍可正常運作。

由索引模型根據 Issue 內容生成。