Make it easier for humans to figure out which configuration of a target failed to build/test

[cbarrete]

When running buck2 build (and also buck2 test after #1394), only the configuration hash gets printed in the output, which is quite unfriendly.

We could instead print the list of modifiers that were applied (if any, otherwise fall back to the current behavior), which are more human readable.

This may however require some bikeshedding about the actual formatting, since it can get quite out of hand when aliases aren't used and/or many are specified. The following example doesn't even have many.

3 TESTS FAILED
  ✗ root//path_to:unit_tests?blah//build/platforms:cxx_standard[26]+blah//build/platforms:compiler[gcc15]+blah//build/platforms:compile_mode[release]
  ✗ root//path_to:unit_tests?blah//build/platforms:cxx_standard[26]+blah//build/platforms:compiler[clang22]+blah//build/platforms:compile_mode[debug]
  ✗ root//path_to:unit_tests?blah//build/platforms:cxx_standard[26]+blah//build/platforms:compiler[clang22]+blah//build/platforms:compile_mode[release]

[8Keep]

cc: @scottcao we've talked about things similar to this kind of problem (repro command) before, wonder if we can just pipe through the ? command line modifiers through

--target-platform, --modifier, and other representative config flags don't matter, because you know which command you gave. Only '?' modifiers matter because you can have multiple targets with different configurations and you want to know which one failed. If you have the hashes (what #1394 does) you can use buck audit configurations to figure it out with some effort, but it's not straightforward). What I wouldn't want is to print the entire configuration, only need the command line modifier for that target really.

@cbarrete can you clarify this in the issue