[UPDATE] Duplicate paragraph in Unit 1 Value-based methods section

# What do you want to improve?

I found a text duplication error in the **Unit 1: Two main approaches for solving RL problems** section under "Value-based methods".

The following paragraph is repeated twice in a row:
>"Thanks to our value function, at each step our policy will select the state with the biggest value defined by the value function: -7, then -6, then -5 (and so on) to attain the goal."

### Location
- **Course Page:** [Two main approaches for solving RL problems](https://huggingface.co/learn/deep-rl-course/unit1/two-methods)
- **Section:** Value-based methods (right under the grid-world image)

I will open a Pull Request shortly to remove the duplicated sentence. Thank you!

Open the Unit 1 course page, “Two main approaches for solving RL problems,” and navigate to the “Value-based methods” section below the grid-world image. Locate the repeated paragraph beginning “Thanks to our value function” and remove the duplicate occurrence. Done means the paragraph appears once and the page text remains correctly formatted.

Written by the indexing model from the issue text.