fix(actions): fix blank lines after ::endgroup:: (#37597) (#37612)

Backport #37597 by @silverwind

`endLogGroup` was incorrectly appending empty `<div>`s, producing a
useless blank line after every group. Before and after:

<img width="250" alt="Screenshot 2026-05-07 at 22 40 40"
src="https://github.com/user-attachments/assets/8baf0fd0-99c8-4648-bf3f-edc6c4b197ec"
/> <img width="250" alt="Screenshot 2026-05-07 at 22 37 12"
src="https://github.com/user-attachments/assets/c45f28ae-1bbf-4b25-9d7b-281c19421f63"
/>

Signed-off-by: silverwind <me@silverwind.io>
Co-authored-by: silverwind <me@silverwind.io>
Co-authored-by: Claude (Opus 4.7) <noreply@anthropic.com>

Author: 3 people

web_src/js/components/ActionRunJobView.vue

@@ -197,10 +197,9 @@ function beginLogGroup(stepIndex: number, startTime: number, line: LogLine, cmd:
 }
 
 // end a log group
-function endLogGroup(stepIndex: number, startTime: number, line: LogLine, cmd: LogLineCommand) {
+function endLogGroup(stepIndex: number) {
   const el = getJobStepLogsContainer(stepIndex);
   el._stepLogsActiveContainer = undefined;
-  el.append(createLogLine(stepIndex, startTime, line, cmd));
 }
 
 // show/hide the step logs for a step
@@ -254,7 +253,7 @@ function appendLogs(stepIndex: number, startTime: number, logLines: LogLine[]) {
         beginLogGroup(stepIndex, startTime, line, cmd);
         continue;
       case 'endgroup':
-        endLogGroup(stepIndex, startTime, line, cmd);
+        endLogGroup(stepIndex);
         continue;
     }
     // the active logs container may change during the loop, for example: entering and leaving a group