feat: more straightforward log for force_shutdown reason

[zhongwencool]

Fixes EMQX-9497

2023-04-10T08:58:32.713601+08:00 [error] failed_to_check_schema: emqx_conf_schema
2023-04-10T08:58:32.717076+08:00 [error] #{kind => validation_error,path => "force_shutdown.max_heap_size",reason => #{exception => 
{error,[102,111,114,99,101,95,115,104,117,116,100,111,119,110,95,112,111,108,105,99,121,58,32,104,101,97,112,45,115,105,122,101,32,"32M",32,105,115,32,116,111,111,32,108,97,114,103,101]},
stacktrace => [{emqx_schema,validate_heap_size,1,[{file,"emqx_schema.erl"},{line,2658}]},{hocon_tconf,do_validate,4,[{file,"hocon_tconf.erl"},{line,1134}]},{hocon_tconf,map_field,4,[{file,"hocon_tconf.erl"},
{line,653}]},{hocon_tconf,map_one_field_non_hidden,4,[{file,"hocon_tconf.erl"},{line,492}]},{hocon_tconf,map_fields_cont,4,[{file,"hocon_tconf.erl"},{line,431}]},{hocon_tconf,map_one_field_non_hidden,4,[{file,"hocon_tconf.erl"},{line,492}]},{hocon_tconf,map_fields_cont,4,[{file,"hocon_tconf.erl"},{line,431}]},{hocon_tconf,map,4,[{file,"hocon_tconf.erl"},{line,301}]}]},value => "32M"}

after:

too large value

force_shutdown.max_heap_size="1000000000000GB"

2023-04-10T11:09:41.776605+08:00 [error] failed_to_check_schema: emqx_conf_schema
2023-04-10T11:09:41.781234+08:00 [error] #{kind => validation_error,path => "force_shutdown.max_heap_size",
reason => #{maximum => 576460752303423487,reason => max_heap_size_too_large},
value => 134217728000000000000}

Bad value 10M, Missing a B, should be 10MB

force_shutdown.max_heap_size="10M"

2023-04-10T11:10:37.129884+08:00 [error] failed_to_check_schema: emqx_conf_schema
2023-04-10T11:10:37.133536+08:00 [error] #{kind => validation_error,path => "force_shutdown.max_heap_size",
reason => invalid_heap_size,value => "10M"}

Summary

🤖 Generated by Copilot at e1e3f77

Refactor the force shutdown policy feature to improve error handling and logging. Change the shutdown reason format to a map with more information, move the validate_heap_size function to emqx_misc and update the test case for check_oom.

PR Checklist

Please convert it to a draft if any of the following conditions are not met. Reviewers may skip over until all the items are checked:

• Added tests for the changes
• Changed lines covered in coverage report
• Change log has been added to changes/{ce,ee}/(feat|perf|fix)-<PR-id>.en.md files
• For internal contributor: there is a jira ticket to track this change
• If there should be document changes, a PR to emqx-docs.git is sent, or a jira ticket is created to follow up
• Schema changes are backward compatible

Checklist for CI (.github/workflows) changes

• If changed package build workflow, pass this action (manual trigger)
• Change log has been added to changes/ dir for user-facing artifacts update

[HJianBo]

LGTM

[coveralls]

Pull Request Test Coverage Report for Build 4689274156

• 1 of 1 (100.0%) changed or added relevant line in 1 file are covered.
• 100 unchanged lines in 18 files lost coverage.
• Overall coverage increased (+0.04%) to 81.12%

---

Files with Coverage Reduction	New Missed Lines	%
apps/emqx_auto_subscribe/src/emqx_auto_subscribe_schema.erl	1	87.5%
apps/emqx_bridge/src/emqx_bridge.erl	1	91.2%
apps/emqx_management/src/emqx_mgmt_util.erl	1	13.79%
apps/emqx/src/emqx_connection.erl	1	87.96%
apps/emqx/src/emqx_channel.erl	2	87.33%
apps/emqx/src/emqx_cm.erl	2	90.99%
apps/emqx/src/emqx_crl_cache.erl	2	92.31%
apps/emqx/src/emqx_stats.erl	2	91.67%
apps/emqx_dashboard/src/emqx_dashboard_swagger.erl	3	96.25%
apps/emqx_exproto/src/emqx_exproto_gcli.erl	3	48.78%

Totals
Change from base Build 4642703850:	0.04%
Covered Lines:	25315
Relevant Lines:	31207

---

💛 - Coveralls