fix: support ##[command] log prefix in action run UI (#37882)

The Actions log parser only recognized `[command]`, so runner command
output emitted as `##[command] ...` was not shown in expanded step logs.

Add `##[command]` support to `LogLinePrefixCommandMap` in
`web_src/js/components/ActionRunView.ts` and cover it with a regression
test in `web_src/js/components/ActionRunView.test.ts`.

Changes
- Fixes Actions UI log rendering for runner command output
- Adds support for ##[command] in the Actions log parser
- Ensures runner echo ... lines are rendered when expanding step logs
- Includes a regression test covering ##[command] foo parsing

Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>

web_src/js/components/ActionRunView.ts

@@ -20,6 +20,7 @@ const LogLinePrefixCommandMap: Record<string, LogLineCommandName> = {
   '##[warning]': 'warning',
   '##[notice]': 'notice',
   '##[debug]': 'debug',
+  '##[command]': 'command',
   '[command]': 'command',
 
   // https://github.com/actions/toolkit/blob/master/docs/commands.md