Bazel 9 and transitions breaks due to flag_alias

[rickeylev]

#3450 added flag_alias() calls in MODULE.bazel, but these break when Bazel 9 and transitions are used together.

The error looks something like:

ERROR: Analysis of target '//tests/bootstrap_impls:bootstrap_script_zipapp_bin' failed; build aborted: no such package '@@rules_python//python/config_settings': The repository '@@rules_python' could not be resolved: Repository '@@rules_python' is not defined

The root cause is something to do with Bazel's handling of the strings passed to flag_alias.

Likely bazelbuild/bazel#28833 but also see the discussion in #3450

In the meantime, we'll remove the aliases and wait for the Bazel fix.