chore: improve integration tests (#8727)

Improve integration tests:
- spliting the tests in TokenExchange to isolated instances and in
parallel
- corrected some test structure so that the check for Details is no done
anymore if the test already failed
- replace required-calls with assert-calls to not stop the testing
- add gofakeit for application, project and usernames(emails)
- add eventually checks for testing in actions v2, so the request only
get called when the execution is defined
- check for length of results in list/search endpoints to avoid index
errors

internal/api/grpc/system/integration_test/instance_test.go

@@ -104,7 +104,7 @@ func TestServer_ListInstances(t *testing.T) {
 			}
 			require.NoError(t, err)
 			got := resp.GetResult()
-			assert.Len(t, got, len(tt.want))
+			require.Len(t, got, len(tt.want))
 			for i := 0; i < len(tt.want); i++ {
 				assert.Equalf(t, tt.want[i].GetId(), got[i].GetId(), "instance[%d] id", i)
 			}