updateState bug fixed for deltaChannel

Changes since 1.2.4

• release(langgraph): 1.2.5 (#8062)
• fix(langgraph): merge lc_versions config metadata (#8052)
• release(cli): 0.4.28 (#8041)
• fix: updateState bug for deltaChannel on empty thread (#8011)
• chore: migrate Python type checking to ty (#8002)
• chore(deps-dev): bump types-requests from 2.33.0.20260408 to 2.33.0.20260518 in /libs/langgraph (#7977)
• chore(deps): bump the minor-and-patch group in /libs/langgraph with 14 updates (#7975)