chore: Bump version to 1.19.0

Workflow run: https://github.com/HumanSignal/label-studio/actions/runs/15161394095

Author: borisheartex

pyproject.toml

@@ -1,6 +1,6 @@
 [project]
 name = "label-studio"
-version = "1.19.0.dev0"
+version = "1.19.0"
 description = "Label Studio annotation tool"
 authors = [
     { name = "HumanSignal", email = "support@humansignal.com" },