Don't trim the message char count for User Feedback Slack Alerts

[Dhrumil-Sentry]

Feedback from a customer on the Slack discussions:

Hello! We are happy with the new notification format, except one small detail: these notifications are now being trimmed to 254 symbols.

It is not convenient for us because not all developers nor support agents, for security reasons, have access to Sentry. Before this change, they were able to read the whole message in Slack.

Is there any chance of keeping the whole User Feedback message when sending it to Slack? Thanks.

Originally posted by @dmitry-textmagic in #61601 (reply in thread)

[getsantry]

Routing to @getsentry/product-owners-settings-integrations for triage ⏲️