Feat invalid Unicode surrogate crash in JSON serialization

[harsh21234i]

Added support for handling invalid UTF-16 surrogate sequences during JSON serialization.

• Introduced SurrogateStrippingStringSerializer to replace invalid surrogate characters with U+FFFD
• Integrated serializer into JacksonMapper
• Added comprehensive tests covering edge cases and reproducing issue invalid unicode sequence crashes kestra executor pod #14806

This prevents crashes when serializing malformed Unicode strings (e.g., PostgreSQL jsonb rejection).
Fixes #14806

[loicmathieu]

I understand the rational but I'm not fan.
Doing this is highly opinionated and would incure a performance cost of reading the whome JSON byte array.

I would prefer that we fail gracely if there is an unsupported character sequence, we already handled that in the queue and he executor I think (we catch the Postgres specific error message and fail the exec).

A better approach may also to have validation whenever possible to avoid such un-processable strings to be set (like in inputs).

[harsh21234i]

Hello @loicmathieu ,
I updated the PR to remove the global surrogate sanitization approach and keep the fix on the existing Postgres queue failure path.

I also tightened the queue-side detection so unsupported Unicode payload failures are still converted to UnsupportedMessageException, including lone surrogate cases, and kept regression coverage on the Postgres queue tests without relying on one exact Postgres error string.

I couldn’t fully verify the Postgres test locally because my local test environment does not currently have Postgres available on localhost:5432, but the code compiles and the change is now targeted to the existing recoverable failure path rather than global string replacement.

[harsh21234i]

Backend tests themselves passed; the failing job is in the reporting step after Gradle and looks related to fork PR permissions ("Resource not accessible
by integration", "Missing organization token"), so it seems unrelated to the code change in this PR.

[loicmathieu]

LGTM