i18n: correct four Italian Knowledge UI translations

### Self Checks

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### Dify version

main, commit 75f867da855234b43dd3c7d570c661447fb2d5c3

### Cloud or Self Hosted

Source review only; not reproduced in a running Cloud or Self Hosted deployment.

### Steps to reproduce

Compare the following keys in `web/i18n/it-IT/dataset.json` with `web/i18n/en-US/dataset.json` on main. This report is based on inspecting the locale files, not a running UI.

| Key | English | Current Italian | Proposed Italian |
| --- | --- | --- | --- |
| chunkingMode.graph | Graph | Grafico | Grafo |
| cornerLabel.pipeline | Pipeline | Infrastruttura | Pipeline |
| batchAction.archive | Archive | Archivio | Archivia |
| docAllEnabled_other | All {{count}} documents enabled | Tutti i documenti {{count}} abilitati | Tutti i {{count}} documenti abilitati |

### ✔️ Expected Behavior

Italian labels should preserve the technical meaning: a graph is a “grafo”, and a processing pipeline should not be labeled as infrastructure. The archive action should use the verb “Archivia”. The plural enabled-documents message should place the count before “documenti”.

I would like to contribute a small PR changing only these four values, preserving all keys and the {{count}} placeholder.

### ❌ Actual Behavior

The Italian locale currently contains the four values listed above, which introduce misleading terminology, a noun used as an action, and unnatural word order.