Update messages_it_IT.properties (#3722)

# Description of Changes

Please provide a summary of the changes, including:

- What was changed
- Why the change was made
- Any challenges encountered

Closes #(issue_number)

---

## Checklist

### General

- [ ] I have read the [Contribution
Guidelines](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/CONTRIBUTING.md)
- [ ] I have read the [Stirling-PDF Developer
Guide](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/DeveloperGuide.md)
(if applicable)
- [ ] I have read the [How to add new languages to
Stirling-PDF](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/HowToAddNewLanguage.md)
(if applicable)
- [ ] I have performed a self-review of my own code
- [ ] My changes generate no new warnings

### Documentation

- [ ] I have updated relevant docs on [Stirling-PDF's doc
repo](https://github.com/Stirling-Tools/Stirling-Tools.github.io/blob/main/docs/)
(if functionality has heavily changed)
- [ ] I have read the section [Add New Translation
Tags](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/HowToAddNewLanguage.md#add-new-translation-tags)
(for new translation tags only)

### UI Changes (if applicable)

- [ ] Screenshots or videos demonstrating the UI changes are attached
(e.g., as comments or direct attachments in the PR)

### Testing (if applicable)

- [ ] I have tested my changes locally. Refer to the [Testing
Guide](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/DeveloperGuide.md#6-testing)
for more details.

stirling-pdf/src/main/resources/messages_it_IT.properties

@@ -348,8 +348,8 @@ account.property=Proprietà
 account.webBrowserSettings=Impostazione del browser web
 account.syncToBrowser=Sincronizza account -> Browser
 account.syncToAccount=Sincronizza account <- Browser
-account.adminTitle=Administrator Tools
-account.adminNotif=You have admin privileges. Access system settings and user management.
+account.adminTitle=Strumenti di amministrazione
+account.adminNotif=Hai privilegi di amministratore. Accedi alle impostazioni di sistema e alla gestione degli utenti.
 
 
 adminUserSettings.title=Impostazioni di controllo utente
@@ -1212,7 +1212,7 @@ merge.header=Unisci 2 o più PDF
 merge.sortByName=Ordina per nome
 merge.sortByDate=Ordina per data
 merge.removeCertSign=Rimuovere la firma digitale nel file unito?
-merge.generateToc=Generate table of contents in the merged file?
+merge.generateToc=Generare un indice nel file unito?
 merge.submit=Unisci