Fix minor issues with postStart script logging

MR: Fix poststart logging (!197372 - closed)

Description

The following discussion from !193265 (merged) should be addressed:

• @vtak commented:

Some things that I noticed which we should take as a followup

• The log file for VS Code has an underscore as opposed to all other logs files which have a hypen.

• While cloning the project, an line is added to the stderr. This seems like an issue with the git client.

Acceptance criteria

• Fix log file naming for the internal_poststart_command_start_vscode.sh script
• Fix git clone writing clone output to poststart-stderr.log