Allow configurability of Slack Issue Alerts to remove some information

### Environment

SaaS (https://sentry.io/)

### Steps to Reproduce

The new sentry slack notifications consume a LOT more screen space:

from

to

Is there _any way_ to get back a more brief version which conserves more screen estate?

They really consume a lot more height now and reduce the overall visibility of the channel they're posted too.

(I suspect it's related to https://github.com/getsentry/sentry/issues/61455)

### Expected Result


### Actual Result


### Product Area

Settings - Integrations

### Link

_No response_

### DSN

_No response_

### Version

_No response_

Review the issue's before-and-after Slack notification examples and related issue #61455 first. Determine which alert information needs to be configurable and confirm the expected brief format from the discussion; done means Slack Issue Alerts can omit selected information while retaining the requested concise presentation.

Written by the indexing model from the issue text.