Remove dependency on CFE_PLATFORM_TLM_MID_BASE in tests

[jphickey]

Checklist (Please check before submitting)

• [x] I reviewed the Contributing Guide.
• [x] I performed a cursory search to see if the bug report is relevant, not redundant, nor in conflict with other tickets.

Describe the bug The LC app depends on CFE_PLATFORM_TLM_MID_BASE which may or may not exist in the user-defined config

To Reproduce Build LC with latest mainline

Expected behavior Should not depend on this symbol

System observed on: Debian

Additional context Unit test issue, does not affect FSW

Reporter Info Joseph Hickey, Vantage Systems, Inc.