docs : Update 4-personalize-codespace.md

[iriru]

Summary

This PR adds a note to the documentation advising users to open a new codespace and wait a sufficient amount of time if errors occur when running commands too soon after opening a codespace.

Changes

• Updated 4-personalize-codespace.md to include a note advising users to wait sufficiently if errors occur.

Extended Description

• Added the following note:
  • Note: Running commands before the codespace is fully set up might result in errors. If an error occurs, please open a new codespace and wait a sufficient amount of time before trying again.

Closes:https://github.com/skills/code-with-codespaces/issues/138

Task list

• [x] Update 4-personalize-codespace.md to include a note advising users to wait sufficiently if errors occur.
• [x] Add a note about opening a new codespace and waiting a sufficient amount of time if errors occur.
• [ ] Review and test the changes.
• [ ] Update the documentation to reflect the changes.
• [ ] Get approval from the team.