[full-ci] Enhance getSpaceByName: check local cache before Graph API calls

[ScharfViktor]

• Added getCreatedSpace() method to fetch spaces from locally saved cache
• Updated getSpaceByName() to:
  • Check local cache first
  • Fetch personal space via Graph API if not in cache
  • Fall back to listing all available spaces via Graph API for users/admins
• Reduced unnecessary API calls and improved performance
• Added inline comments explaining the logic

[rhafer]

I think there is a minor error in one of the comments.
Also (optionally) there might be "easier" endpoints for getting the personal space of a specific user.