Bug: Status notifications fail AWS SNS message validation

[patheard]

Summary

When the Status page is posting SNS messages through the SRE Bot, the following error is thrown:

Extra inputs are not permitted [type=extra_forbidden, input_value='🟩 GC Forms - Formulai....canada.ca/) is back up', input_type=str]

INFO:root:Ops msg: Error parsing AWS event due to ValidationError: ```
{
    "text": "🟩 GC Forms - Formulaires GC (https://forms-formulaires.alpha.canada.ca/) is back up"
}

ERROR:root:1 validation error for AwsSnsPayload: text

This prevents the message from being posted properly.

[gcharest]

Fixed in #653