CXX-2338 migrate clang-tidy task to rhel96

[eramongodb]

Addresses CXX-2338 by avoiding the need to run yum install parallel in the run-clang-tidy.sh script. DEVPROD-23486 is still in-progress, but verified via patch build that parallel has been deployed to the rhel96 distro (current target for the rhel9-latest distro alias).

As a drive-by improvement, formats the output of the list of files being analyzed to contain a - prefix:

# Before
Scanning the following files:
src/bsoncxx/include/bsoncxx/docs/top.hpp
src/bsoncxx/include/bsoncxx/docs/topics.hpp
src/bsoncxx/include/bsoncxx/docs/v1.hpp
...

# After
Scanning the following files:
 - src/bsoncxx/include/bsoncxx/docs/top.hpp
 - src/bsoncxx/include/bsoncxx/docs/topics.hpp
 - src/bsoncxx/include/bsoncxx/docs/v1.hpp
...

[eramongodb]

verified via patch build that parallel has been deployed

Sorry, looks like I spoke too soon: the command check revealed a workaround for not-yet-audited clang-tidy configuration was also silencing "command not found" errors and diagnostic output. parallel doesn't appear to have been deployed yet. It looks like this workaround was added by #1049 with a TODO comment as part of EVG refactors, but did not have a proper followup since.