Revert "Fix FastAPI discriminated union patch to be called consistently"

[xingyaoww]

Reverts #1256

We should not import openhands.agent_server inside openhands.sdk - this will cause dependency issue as ppl install sdk won't necessarily install agent_server

---

Agent Server images for this PR

• GHCR package: https://github.com/OpenHands/agent-sdk/pkgs/container/agent-server

Variants & Base Images

Variant	Architectures	Base Image	Docs / Tags
java	amd64, arm64	eclipse-temurin:17-jdk	Link
python	amd64, arm64	nikolaik/python-nodejs:python3.12-nodejs22	Link
golang	amd64, arm64	golang:1.21-bookworm	Link

Pull (multi-arch manifest)

# Each variant is a multi-arch manifest supporting both amd64 and arm64
docker pull ghcr.io/openhands/agent-server:20d17b4-python

Run

docker run -it --rm \
  -p 8000:8000 \
  --name agent-server-20d17b4-python \
  ghcr.io/openhands/agent-server:20d17b4-python

All tags pushed for this build

ghcr.io/openhands/agent-server:20d17b4-golang-amd64
ghcr.io/openhands/agent-server:20d17b4-golang_tag_1.21-bookworm-amd64
ghcr.io/openhands/agent-server:20d17b4-golang-arm64
ghcr.io/openhands/agent-server:20d17b4-golang_tag_1.21-bookworm-arm64
ghcr.io/openhands/agent-server:20d17b4-java-amd64
ghcr.io/openhands/agent-server:20d17b4-eclipse-temurin_tag_17-jdk-amd64
ghcr.io/openhands/agent-server:20d17b4-java-arm64
ghcr.io/openhands/agent-server:20d17b4-eclipse-temurin_tag_17-jdk-arm64
ghcr.io/openhands/agent-server:20d17b4-python-amd64
ghcr.io/openhands/agent-server:20d17b4-nikolaik_s_python-nodejs_tag_python3.12-nodejs22-amd64
ghcr.io/openhands/agent-server:20d17b4-python-arm64
ghcr.io/openhands/agent-server:20d17b4-nikolaik_s_python-nodejs_tag_python3.12-nodejs22-arm64
ghcr.io/openhands/agent-server:20d17b4-golang
ghcr.io/openhands/agent-server:20d17b4-java
ghcr.io/openhands/agent-server:20d17b4-python

About Multi-Architecture Support

• Each variant tag (e.g., 20d17b4-python) is a multi-arch manifest supporting both amd64 and arm64
• Docker automatically pulls the correct architecture for your platform
• Individual architecture tags (e.g., 20d17b4-python-amd64) are also available if needed

[github-actions]

Coverage Report •

File	Stmts	Miss	Cover	Missing
openhands-sdk/openhands/sdk/utils
models.py	161	42	73%	24–25, 52, 54, 86–87, 91–92, 96–97, 103–104, 136–139, 159, 162, 164–165, 167–172, 174–175, 180, 223, 243–244, 246–248, 256–258, 260–262, 281
TOTAL	6935	4341	37%