Make default schema a required argument in ExecutionEndpoint

Is your feature request related to a problem? Please describe. In the current setup, the ExecutionEndpoint takes a default schema if one is not provided through parameters. We want to remove this default schema so that it becomes a mandatory argument. Additionally, any constants related to this default schema in orchestrator_constants should be removed. Describe the solution you'd like The schema argument, which is already passed in the current version, should now be mandatory, and the default schema should no longer be applied automatically. Additional context This update may also require changes to documentation or examples where the default schema is assumed.