That’s due to a simple typo. There’s an unnecessary space character in the word entity _id. It should be entity_id.
If the light increases to 100% much faster than 5 minutes, then it doesn’t support the transition command.
ChatGPT has proven to be an unreliable source for automations and scripts. Please do not post non-functional examples created by ChatGPT. For more information, refer to this blog post.
If you want to dim/brighten a light over a long period of time, and it doesn’t support transition, then you will need to use a script that sends consecutive discrete commands. The problem was discussed and resolved in the following topic:
Here’s another solution to the same problem that also offers non-linear fading.