A single instance with a malformed `enable` value (e.g. the typo `enable`
instead of `enabled`/`on`) made every configured notification/audit target
of every type fail to load. `create_targets_from_config_with_store_mode`
collected instance configs through the strict `try_collect_target_configs`,
whose `.collect::<Result<Vec, _>>()` short-circuits on the first error and
drops all siblings; the surrounding `?` then aborted the loop over every
plugin type.
This contradicted the function's own documented contract ("Creation is
fault-isolated per instance") and was inconsistent: target construction
failures were already isolated into the `failures` accumulator, only config
collection failures were fatal.
Add `collect_target_config_results[_from_env]`, which returns the enabled
`(id, config)` pairs plus a per-instance failure summary, and use it in the
create path. Per-instance collection errors now flow into the same
`failures`/`creation_failures` accumulator as construction failures: healthy
siblings and other target types still load, while the malformed instance is
surfaced so the notify lifecycle stays non-converged/retryable and an Admin
write cannot report a false success. Audit likewise keeps logging through
its valid targets instead of going fully Stopped.
Follow-up to #5088.
Zhengchao An