client: fix submitpfb namespace hack

[tuxcanfly]

Overview

This PR removes the namespace hack for submit_pfb request which was introduced in #56

Checklist

• [x] New and updated code has appropriate documentation
• [x] New and updated code has new and/or updated testing
• [x] Required CI checks are passing
• [x] Visual proof for any user facing features like CLI or documentation updates
• [x] Linked issues closed with keywords

[tuxcanfly]

Blocked by #62

[MSevey]

made draft until unblocked.

[tuxcanfly]

Followed up in #61