firstlogin: quote values if space is legal

[jkt628]

Description

Please include a summary of the change and which issue is fixed. Please also include relevant motivation and context. List any dependencies that are required for this change.

GitHub issue reference: #6940
Jira reference number AR-2419

How Has This Been Tested?

Please describe the tests that you ran to verify your changes. Please also note any relevant details for your test configuration.

• Test A
  • create /root/.not_logged_in_yet as noted in [Bug]: firstlogin mishandles many PRESET_ values containing spaces #6940
  • notice the errors disappear

Checklist:

Please delete options that are not relevant.

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• My changes generate no new warnings

[EvilOlaf]

lgtm

[igorpecovnik]

Thank you for looking into!

[amazingfate]

Good job!