[BUG] ubuntu文件系统/可用量显示存在bug

### Is there an existing issue for this?

- [X] I have searched the existing issues

### Current Behavior

在ubuntu服务器监控详情里面，文件系统/可用量显示存在bug，可能是因为挂载了docker相关的内容，导致文件名称比较长。

### Expected Behavior

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### Steps To Reproduce

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### Environment

```markdown
HertzBeat version(1.15):
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### Debug logs

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### Anything else?

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The issue concerns filesystem available-space display in the Ubuntu server monitoring details, especially when Docker-related mount names are long. Start by reproducing the display with a long mounted filesystem name and inspect the monitoring detail view. Done means filesystem names and available-space values remain readable and accurate.

Written by the indexing model from the issue text.