Callstack on Slack integration

### Problem Statement

For fast debug and understand what is happening, is important to have a callstack in notification on slack, the last info the crash report capture and replicate in slack, not allways indicate the real root case, in UnrealEngine the callstack is crtical to detemrinate what is the root of problem.
(more then one error can have the same final function)

### Solution Brainstorm

Allow to include callstack in slack notification, as Backtrace do.

### Product Area

Settings - Integrations

Start with Settings - Integrations and trace the Slack notification flow. Determine how the crash report callstack should be included in Slack and define the expected notification content, including how existing crash details remain represented.

Written by the indexing model from the issue text.