Remove error message in case of unsupported content types

[tillprochaska]

When we receive a message that contains attachments or uses messenger features we do not support, we currently send an auto-reply to the contributor:

Our software can currently handle text messages, voice messages and images, but not yet other content such as stickers, file attachments or contacts. For the meantime, please send messages with such content to XYZ. Thank you very much!

I suggest we remove those auto-replys. Most of the time, we manually retrieve those attachemnts anyways, i.e. there’s no need for the contributor to re-send the message. More importantly, this isn’t very user friendly and it breaks our promise of personal, 1:1 communication.

Additionally, there are cases where the reason for the auto-reply isn’t directly related to the contributor’s message (e.g. #1337).

Instead, we should log such cases to Sentry so we can implement support for frequently used messenger features etc.

[drjakob]

I support this

[FrauCsu]

Let's do this.