ohos: Remove catch in sign script so that the error is propogated and not ignored

[janeoa]

In the current state, when running

uv run main.py ~/path-to-build-profile.json5

from the docker/runner/signing-util, there is a case when it fails:

When the build-profile.json5 is valid, but material dir is not present, the script will still print out "File sign.sh written" and the file will actually be written. But instead of expected contents, the file would have a node error message inside it. Because the python does

return subprocess.check_output(["node", "sign.js", path, password])

but the JS:

...
    } catch (e) {
      console.log(e);
    }

so the current PR just removes the catch, so that the error can propagate and now python returns full error message into the stdout and does not produce the sign.sh

[Narfinger]

Looks good. Thanks for the cleanup!