Describe the bug
A previous PR I made (#6664 ) broke the mailer pipeline : by changing the smtp_settings from a string hash to a symbol hash, the production server does not recognize port, dns etc.

https://github.com/decidim/decidim/pull/6664/files#diff-e88842de6b18dbdb3f7d09864444e1ed2c066e26b30f29459a03082474d44dc6

        address: @organization.smtp_settings["address"],
        port: @organization.smtp_settings["port"],
        user_name: @organization.smtp_settings["user_name"],
        password: Decidim::AttributeEncryptor.decrypt(@organization.smtp_settings["encrypted_password"])

was wrongly replaced by

        address: @organization.smtp_settings[:address],
        port: @organization.smtp_settings[:port],
        user_name: @organization.smtp_settings[:user_name],
        password: Decidim::AttributeEncryptor.decrypt(@organization.smtp_settings[:encrypted_password])

The error wasn't detected as the mail sending is not currently tested

To Reproduce
Steps to reproduce the behavior:

1. Correct smtp_settings in system
2. Click update
3. Check

Extra data (please complete the following information):

• Device: [e.g. iPhone6, Desktop]
• Device OS: [e.g. iOS8.1, Windows 10]
• Browser: [e.g. Chrome, Firefox, Safari]
• Decidim Version: [e.g. 0.10]
• Decidim installation: [e.g. MetaDecidim]

Additional context
Add any other context about the problem here. For instance, add Metadecidim link.