[Bug] Timeout export job sometimes stuck in exporting state

[xy720]

Describe the bug
Sometimes export job will stuck in exporting state when it times out.

To Reproduce
Steps to reproduce the behavior:

1. start a export job and set a very short timeout.

export table testTbl to "hdfs://xxx:54310/app/xxx/palo/test_table/" properties ("timeout" = "3") with broker "doris" ("username" = "xxx", "password" = "xxx");

2. export job will stuck in exporting state.

Expected behavior
The timeout export job should be canceled.

Screenshots

Desktop (please complete the following information):

• OS: [e.g. iOS]
• Browser [e.g. chrome, safari]
• Version [e.g. 22]

Smartphone (please complete the following information):

• Device: [e.g. iPhone6]
• OS: [e.g. iOS8.1]
• Browser [e.g. stock browser, safari]
• Version [e.g. 22]

Additional context
Add any other context about the problem here.