Describe the bug
When compiling in a project with no tests, but a (empty) tests file exists, the compile fails with the following error:

[ 50%] Linking CXX executable test
CMake Error at /usr/lib/cmake/Catch2/CatchAddTests.cmake:150 (string):
  string sub-command JSON expected an index less than 0 got '0'.
Call Stack (most recent call first):
  /usr/lib/cmake/Catch2/CatchAddTests.cmake:228 (catch_discover_tests_impl)

Expected behavior
The project should compile correctly.

Reproduction steps
Steps to reproduce the bug.

1. Create base project directory (base_dir)
2. Add CMakeLists.txt (CMakeLists.txt)
3. Create tests directory inside base (base_dir/tests)
4. Create an empty test file inside base (base_dir/tests/tests.cpp)
5. Create build directory inside base (base_dir/build)
6. cd into build directory
7. Run cmake ..
8. Run make -> an error occurs

Platform information:

• OS: Ubuntu 24.04.1 LTS arm64
• Compiler+version: clang 18.1.3 (1ubuntu1)
• Catch version: v3.8.0

Additional context