incompatibility with Lmod 8.7.56 due to module show producing non-zero exit code for non-existent module

[boegel]

Upgrading the Lmod 8.7.56 causes trouble for EasyBuild, because it includes a backwards-incompatible change: running module show on a non-existing module file now returns a non-zero exit code (while before it always resulted in exit code 0, regardless of whether the module file exists or not). See also TACC/Lmod#743 .

It's very easy to run into this after upgrading Lmod to version 8.7.56 (or newer), since EasyBuild checks very early on whether modules for dependencies exist through the ModulesTool.exist method, which relies module show in case a module file is not listed in module avail.
For example:

eb bzip2-1.0.8.eb -r
== Temporary log file in case of crash /tmp/eb-h1puymlz/easybuild-qleyna3p.log
== resolving dependencies ...
ERROR: Module command '/opt/homebrew/Cellar/lmod/8.7.56/libexec/lmod python show binutils/2.37' failed with exit code 1; stderr: Lmod has detected the following error: Failed to find the following module(s): "binutils/2.37" in your MODULEPATH
Try:

    $ module spider binutils/2.37

to see if the module(s) are available across all compilers and MPI implementations.



; stdout: _mlstatus = False

[boegel]

Fixed for upcoming EasyBuild 5.0 in #4739, but keeping this open since I hope that with a small additional change the breaking change in Lmod can be made conditional so that compatibility with EasyBuild 4.x and recent Lmod versions can be retained...

cc @rtmclay