bug(linux): X11-024___options_with_save_and_preset__surrounding-text test seems unstable

https://build.palaso.org/buildConfiguration/Keyman_Linux_Test_Integration/610616?buildTab=log&linesState=90&logView=flowAware&expandAll=true&focusLine=2032

```
10:25:21  # Starting tests...
10:25:21  ** Message: 05:25:21.676: keyman_put_keyboard_options_todconf: saving keyboard option to DConf for k_024___options_with_save_and_preset/k_024___options_with_save_and_preset: foo=1
10:25:21  **
10:25:21  ERROR:../../../ibus-keyman/tests/testfixture.cpp:208:void test_source(IBusKeymanTestsFixture*, gconstpointer): assertion failed (options[i] == expected): ("foo=1" == "foo=0")
10:25:21 
10:25:21  (test program exited with status code 1)

...
Summary of Failures:

28/218 X11-024___options_with_save_and_preset__surrounding-text ERROR 0.31s exit status 1

Ok: 209
Expected Fail: 0
Fail: 1
Unexpected Pass: 0
Skipped: 8
Timeout: 0
```

See also
https://build.palaso.org/buildConfiguration/Keyman_Linux_Test_Integration/610520?buildTab=log