Regression in v2.1.0: Warnings for parameterised tests

[tobiasleibner]

Expected Behavior

Parameterized tests should work without warnings.

Actual Behavior

Parameterized tests result in warnings like

WARNING test 'types' for test suite 'global' already present

The tests seems to be run for all parameters, though, so the warnings seems to be harmless (?).

Steps to Reproduce the Problem

1. Open example from the documentation on parameterized tests on Godbolt (https://godbolt.org/z/4xGGdo)
2. Compile and run the example (using x86_64 GCC 14.2, -std=c++20) -> The warnings show up when executing the test (and there are a few compiler warnings during the compilation but that is not the subject of this issue)
3. Change the include to
   #include <https://raw.githubusercontent.com/boost-experimental/ut/v2.0.0/include/boost/ut.hpp>
   -> The warnings are gone
4. Change the include to
   #include <https://raw.githubusercontent.com/boost-experimental/ut/v2.1.0/include/boost/ut.hpp>
   -> The warnings appear again.