Force English content in whatsapp_ip_addresses_download.sh

[fabiodepin]

Please sign (check) the below before submitting the Pull Request:

• [ X ] I have signed the ntop Contributor License Agreement at https://github.com/ntop/legal/blob/main/individual-contributor-licence-agreement.md
• [ X ] I have read the contributing guidelines at https://github.com/ntop/nDPI/blob/dev/CONTRIBUTING.md
• [ - ] I have updated the documentation (in doc/) to reflect the changes made (if applicable)

Link to the related issue:
#2700

Describe changes:
Add the Accept-Language header in the cURL command to ensure the fetched page is in English, improving consistency and clarity in the script output.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[IvanNardi]

Thanks for the patch. It does fix an issue that I have been having locally.