fix: add information about target response into error message if inte… (#8281)

# Which Problems Are Solved

Execution responses with HTTP StatusCode not equal to 200 interrupt the
client request silently.

# How the Problems Are Solved

Adds information about the recieved StatusCode and Body into the error
if StatusCode not 200.

# Additional Context

Closes #8177

---------

Co-authored-by: Elio Bischof <elio@zitadel.com>
Co-authored-by: Livio Spring <livio.a@gmail.com>

docs/docs/apis/actionsv2/introduction.md

@@ -169,4 +169,19 @@ For event there are 3 levels the condition can be defined:
 - Group, handling a specific group of events
 - All, handling any event in ZITADEL
 
-The concept of events can be found under [Events](/concepts/architecture/software#events)
+The concept of events can be found under [Events](/concepts/architecture/software#events)
+
+### Error forwarding
+
+If you want to forward a specific error from the Target through ZITADEL, you can provide a response from the Target with status code 200 and a JSON in the following format:
+
+```json
+{
+  "forwardedStatusCode": 403,
+  "forwardedErrorMessage": "Call is forbidden through the IP AllowList definition"
+}
+```
+
+Only values from 400 to 499 will be forwarded through ZITADEL, other StatusCodes will end in a PreconditionFailed error.
+
+If the Target returns any other status code than >= 200 and < 299, the execution is looked at as failed, and a PreconditionFailed error is logged.