[RCORE-2146] CAPI Remove is_fatal flag flip (#7751)

Author: clementetb

CHANGELOG.md

@@ -10,6 +10,7 @@
 * Fixed removing backlinks from the wrong objects if the link came from a nested list, nested dictionary, top-level dictionary, or list of mixed, and the source table had more than 256 objects. This could manifest as `array_backlink.cpp:112: Assertion failed: int64_t(value >> 1) == key.value` when removing an object. ([#7594](https://github.com/realm/realm-core/issues/7594), since v11 for dictionaries)
 * Fixed the collapse/rejoin of clusters which contained nested collections with links. This could manifest as `array.cpp:319: Array::move() Assertion failed: begin <= end [2, 1]` when removing an object. ([#7839](https://github.com/realm/realm-core/issues/7839), since the introduction of nested collections in v14.0.0-beta.0)
 * wait_for_upload_completion() was inconsistent in how it handled commits which did not produce any changesets to upload. Previously it would sometimes complete immediately if all commits waiting to be uploaded were empty, and at other times it would wait for a server roundtrip. It will now always complete immediately. ([PR #7796](https://github.com/realm/realm-core/pull/7796)).
+* `realm_sync_session_handle_error_for_testing` parameter `is_fatal` was flipped changing the expected behavior. (#[7750](https://github.com/realm/realm-core/issues/7750)).
 
 ### Breaking changes
 * None.

src/realm/object-store/c_api/sync.cpp

@@ -836,7 +836,7 @@ RLM_API void realm_sync_session_handle_error_for_testing(const realm_sync_sessio
     REALM_ASSERT(session);
     SyncSession::OnlyForTesting::handle_error(
         *session->get(),
-        sync::SessionErrorInfo{Status{static_cast<ErrorCodes::Error>(error_code), error_str}, !is_fatal});
+        sync::SessionErrorInfo{Status{static_cast<ErrorCodes::Error>(error_code), error_str}, is_fatal});
 }
 
 } // namespace realm::c_api