Fixes numbering sequence in conda environment setup instructions (#3048)

# Description

This PR fixes a minor numbering sequence issue in the conda environment
setup instructions displayed by `isaaclab.sh`.

- Fixed step numbering from "4. To perform formatting" to "3. To perform
formatting"
- Fixed step numbering from "5. To deactivate the environment" to "4. To
deactivate the environment"

## Type of change

- [x] Bug fix (non-breaking change which fixes an issue)
- [ ] New feature (non-breaking change which adds functionality)
- [ ] Breaking change (fix or feature that would cause existing
functionality to not work as expected)
- [ ] This change requires a documentation update

## Checklist

- [ ] I have run the [`pre-commit` checks](https://pre-commit.com/) with
`./isaaclab.sh --format`
- [ ] I have made corresponding changes to the documentation
- [x] My changes generate no new warnings
- [ ] I have added tests that prove my fix is effective or that my
feature works
- [ ] I have updated the changelog and the corresponding version in the
extension's `config/extension.toml` file
- [x] I have added my name to the `CONTRIBUTORS.md` or my name already
exists there

CONTRIBUTORS.md

@@ -127,6 +127,7 @@ Guidelines for modifications:
 * Yang Jin
 * Yanzi Zhu
 * Yijie Guo
+* Yohan Choi
 * Yujian Zhang
 * Yun Liu
 * Ziqi Fan

isaaclab.sh

@@ -287,8 +287,8 @@ setup_conda_env() {
     echo -e "[INFO] Created conda environment named '${env_name}'.\n"
     echo -e "\t\t1. To activate the environment, run:                conda activate ${env_name}"
     echo -e "\t\t2. To install Isaac Lab extensions, run:            isaaclab -i"
-    echo -e "\t\t4. To perform formatting, run:                      isaaclab -f"
-    echo -e "\t\t5. To deactivate the environment, run:              conda deactivate"
+    echo -e "\t\t3. To perform formatting, run:                      isaaclab -f"
+    echo -e "\t\t4. To deactivate the environment, run:              conda deactivate"
     echo -e "\n"
 }