Whatsapp add " (edited)" after the configured EditSuffix

[nathanaelhoun]

Describe the bug
A clear and concise description of what the bug is.
Matterbridge is always adding the " (edited)" suffix, even when EditSuffix is configured.

To Reproduce
Steps to reproduce the behavior:

• Bridge whatsapp and another service which supports editing (like Mattermost, Discord)
• Configure EditSuffix, either globally or for Whatsapp
• Edit the message
• See the problem

Expected behavior
A clear and concise description of what you expected to happen.
The string configured in EditSuffix should replace the " (edited)" suffix.

Screenshots/debug logs
If applicable, add screenshots to help explain your problem.
Use logs from running matterbridge -debug if possible.

Environment (please complete the following information):

• OS: linux
• Matterbridge version: version: 1.22.2 641ed18
• If self compiled: output of git rev-parse HEAD

Additional context
Please add your configuration file (be sure to exclude or anonymize private data (tokens/passwords))

I wanted to PR this change 0303af4 but looking to the code, I think the string will be empty if EditSuffix is not configured, which may be a problem.