Update Learning-Environment-Create-New.md (#4554)

Point 2 and 5 are duplicates. Removed redundant information.

docs/Learning-Environment-Create-New.md

 1. Add the `Decision Requester` script with the Add Component button from the
    RollerAgent Inspector.
 1. Change **Decision Period** to `10`. For more information on decisions, see [the Agent documentation](Learning-Environment-Design-Agents.md#decisions)
-1. Drag the Target GameObject from the Hierarchy window to the RollerAgent
-   Target field.
 1. Add the `Behavior Parameters` script with the Add Component button from the
    RollerAgent Inspector.
 1. Modify the Behavior Parameters of the Agent :