timeout when run test in an env without browser

[lidaobing]

$ xvfb-run meson test
ninja: Entering directory `/home/lidaobing/workspace/lidaobing/iptux/build'
ninja: no work to do.
1/4 iptux utils unit test         OK              0.03s
2/4 iptux core unit test          OK              1.31s
3/4 iptux ui unit test            TIMEOUT        30.02s
>>> UBSAN_OPTIONS=halt_on_error=1:abort_on_error=1:print_summary=1:print_stacktrace=1 MALLOC_PERTURB_=168 ASAN_OPTIONS=halt_on_error=1:abort_on_error=1:print_summary=1 LD_LIBRARY_PATH=/home/lidaobing/workspace/lidaobing/iptux/build/src/iptux-core /home/lidaobing/workspace/lidaobing/iptux/build/src/iptux/libiptux_test

4/4 validate metainfo file        OK              0.04s

Ok:                 3   
Expected Fail:      0   
Fail:               0   
Unexpected Pass:    0   
Skipped:            0   
Timeout:            1   

Full log written to /home/lidaobing/workspace/lidaobing/iptux/build/meson-logs/testlog.txt
Exception ignored in: <function BaseSubprocessTransport.__del__ at 0x7ffbbfa2ba60>
Traceback (most recent call last):
  File "/usr/lib/python3.11/asyncio/base_subprocess.py", line 126, in __del__
    self.close()
  File "/usr/lib/python3.11/asyncio/base_subprocess.py", line 104, in close
    proto.pipe.close()
  File "/usr/lib/python3.11/asyncio/unix_events.py", line 566, in close
    self._close(None)
  File "/usr/lib/python3.11/asyncio/unix_events.py", line 590, in _close
    self._loop.call_soon(self._call_connection_lost, exc)
  File "/usr/lib/python3.11/asyncio/base_events.py", line 762, in call_soon
    self._check_closed()
  File "/usr/lib/python3.11/asyncio/base_events.py", line 520, in _check_closed
    raise RuntimeError('Event loop is closed')
RuntimeError: Event loop is closed

reason: iptux_open_url should exit if no browser detected.