Missing DEPENDS causes strange error

| | |
|:---|:---|
|**_F´ Version_**| 4.x|
|**_Affected Component_**|   |
---
## Problem Description

If a module `CMakeLists.txt` has an empty `DEPENDS` section in the `register_fprime_library` function call, the `fprime-util generate` step will emit a bizarre error:

```
CMake Error at lib/fprime/cmake/utilities.cmake:788 (message):
   ----------------------------------------
   F Prime/CMake target 'TRUE' not available to deployment 'SomeDeployment'. 'TRUE' must:
       1. Must be defined somewhere in the F Prime project
       2. Must be defined before 'SomeDeployment' deployment (register_fprime_deployment)
   'TRUE' is undefined, or included via `add_fprime_subdirectory` after `register_fprime_deployment`. in:
       /home/tcanham/source/SomeDirectory/Something/CMakeLists.txt
   ----------------------------------------

Call Stack (most recent call first):
  lib/fprime/cmake/utilities.cmake:737 (fprime_cmake_clear_message)
  lib/fprime/cmake/target/target.cmake:75 (fprime_cmake_fatal_error)
  lib/fprime/cmake/target/target.cmake:136 (check_unknown_links)
  lib/fprime/cmake/target/target.cmake:181 (setup_single_target)
  lib/fprime/cmake/API.cmake:161 (setup_module_targets)
  lib/fprime/cmake/API.cmake:346 (fprime_attach_custom_targets)
  SomeDeploymentDirectory/CMakeLists.txt:19 (register_fprime_deployment)
```

(Fake directories and names were inserted into the error text)

## Context / Environment

Execute `fprime-util version-check` and share the output.

```
Operating System: Linux
CPU Architecture: x86_64
Platform: Linux-5.15.133.1-microsoft-standard-WSL2-x86_64-with-glibc2.39
Python version: 3.12.3
CMake version: 3.26.0
Pip version: 26.1.1
Pip packages:
    fprime-tools==4.2.1
    fprime-gds==4.2.1
    fprime-fpp==3.2.0
Project submodules:
    https://github.com/nasa/fprime.git @ v4.2.2
```

## How to Reproduce

1.  Take any module directory with no `DEPENDS` in the `register_fprime_library`
2.  Add `DEPENDS` with no string
3.  Run fprime-util generate

## Expected Behavior

It would be nice to have an error that is more informative like "Empty DEPENDS, dummy!"

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