`Bundle` EasyBlock might not load all modules during components sanity check(?)

[Thyre]

We are investigating build failures in easybuilders/easybuild-easyconfigs#23304.

Builds fail on jsc-zen3 with:

ERROR EasyBuild encountered an error: Sanity check failed: sanity check command cd /tmp/eb-gsz9cy5u/tmpcc33p7ik && g++ minimal.cpp -o minimal_cpp $(llvm-config --link-static --system-libs all) failed with exit code 1 (output: /project/def-maintainers/boegelbot/rocky9/zen3/software/binutils/2.42-GCCcore-14.2.0/bin/ld: cannot find -lxml2: No such file or directory

However, libxml2 is a clear dependency and should be available.
A similar test with LLVM converted to an EasyBlock, and some hacky changes to work around #4008 resulted in a similar failure locally:

  >> running command 'cd /tmp/eb-cs7_qwi5/tmpv1ymtzr5 && g++ minimal.cpp -o minimal_cpp $(llvm-config --link-static --system-libs all)' ...
  >> result for command 'cd /tmp/eb-cs7_qwi5/tmpv1ymtzr5 && g++ minimal.cpp -o minimal_cpp $(llvm-config --link-static --system-libs all)': FAILED
== ... (took 12 secs)
== FAILED: Installation ended unsuccessfully: Sanity check failed: sanity check command cd /tmp/eb-cs7_qwi5/tmpv1ymtzr5 && g++ minimal.cpp -o minimal_cpp $(llvm-config --link-static --system-libs all) failed with exit code 1 (output:
/opt/EasyBuild/apps/software/binutils/2.44-GCCcore-14.3.0/bin/ld: cannot find -lzstd: No such file or directory
/opt/EasyBuild/apps/software/binutils/2.44-GCCcore-14.3.0/bin/ld: cannot find -lxml2: No such file or directory

I'm therefore guessing that this might be a bug in the Bundle EasyBlock where components aren't loading modules correctly?
What doesn't make sense is that we have a successful test report from EB 5.1.2 by @bedroge (see easybuilders/easybuild-easyconfigs#23304 (comment)), but there are almost no changes to Bundle since then. The specific LLVM check was also already in EB 5.1.2 (see 0c3956b and c7300cd)