Obsolete installation message when importing via amuse.lab

[LourensVeen]

Describe the bug When I made the new build system, I made it so that if you import a code that isn't available from amuse.community.<code>, you get a nice error that tells you how to install it, depending on whether we're in a venv or a conda environment.

What I failed to notice was that you can also install from amuse.lab, and that that has its own error message, which currently reads:

Traceback (most recent call last):
  File "/data2/lveen/amuse-2025.9.0/examples/textbook/gravity_minimal.py", line 26, in <module>
    gravity_minimal(N, t_end)
    ~~~~~~~~~~~~~~~^^^^^^^^^^
  File "/data2/lveen/amuse-2025.9.0/examples/textbook/gravity_minimal.py", line 8, in gravity_minimal
    gravity = Hermite()
  File "/data2/lveen/miniforge3/envs/Amuse-env/lib/python3.14/site-packages/amuse/lab.py", line 133, in __init__
    raise Exception(
        "failed import, code {0} not available, maybe it needs to be "
        "(pip) installed?".format(name))
Exception: failed import, code hermite not available, maybe it needs to be (pip) installed?

We don't want people to pip install anymore. For comparison, when importing from amuse.community it says:

Traceback (most recent call last):
  File "/data2/lveen/amuse-2025.9.0/examples/textbook/gravity_minimal.py", line 1, in <module>
    from amuse.community.hermite import Hermite
  File "/data2/lveen/miniforge3/envs/Amuse-env/lib/python3.14/site-packages/amuse/community/hermite/__init__.py", line 1, in <module>
    from .interface import Hermite
  File "/data2/lveen/miniforge3/envs/Amuse-env/lib/python3.14/site-packages/amuse/community/hermite/interface.py", line 4, in <module>
    HermiteInterface = load_code("hermite", "HermiteInterface")
  File "/data2/lveen/miniforge3/envs/Amuse-env/lib/python3.14/site-packages/amuse/support/import_helper.py", line 38, in load_code
    raise ImportError(msg) from None
ImportError: Error: hermite is not installed, so we cannot use it. To install hermite, go to the terminal, make sure that the 'Amuse-env' conda environment is active and that you are in the amuse source directory, then install the code using './setup install amuse-hermite' and restart your script or reload the kernel.

To Reproduce from amuse.lab import Hermite with Hermite not installed.

Expected behavior The second error message above to be displayed