Fix race-condition reading job module details files

[okurz]

A not readable test module result file is handled and gracefully
returned to the web UI and no error in log. The handling should be
atomic, not "check if readable and then read". Instead of trying to read
and then fail we should handle the read attempt as we handle the
exception in line 96 and return {} in case of error.

Related progress issue: https://progress.opensuse.org/issues/121444

[perlpunk]

I thought the conclusion in our meeting was that we do not want an exception if the file is not there (return {})

[okurz]

I thought the conclusion in our meeting was that we do not want an exception if the file is not there (return {})

I wanted to see test results and based on those see if maybe the exceptions are already handled on a higher level and turned into properly returned error messages

[asdil12]

I thought the conclusion in our meeting was that we do not want an exception if the file is not there (return {})

I think the idea is that we do want to use exceptions to handle that error because they don't introduce race conditions where we can still run into the issue, but catch those exceptions and return something like 404 to the client.

[okurz]

Updated the PR to explicitly return {} as originally discussed. This also means that tests pass again as the same path is taken as if the complete result directory is not readable anymore.