refactor(mobile): move error details to separate DB column

[rovo89]

As discussed in #6866, logRecord.error previously wasn't stored in the DB. Instead, a string copy of it was merged into the message in most places. Separate the two, so the log overview shows a brief description of the error while the details (usually an exception, but could be any string) can be found in the details page.

I adjusted many places to split the log message into its headline and the details, but for sure there will be some that I've missed. It shouldn't be a problem to adjust those later. There might also be places where adding further details as string could be helpful, like a few statistics when the upload has finished.

[rovo89]

@shenlong-tanwen: PTAL

[shenlong-tanwen]

Thanks a lot for the PR!

[shenlong-tanwen]

LGTM!

[rovo89]

That's funny... first it complains that

          final failedResponse =
              imageResponse.statusCode != 200 ? imageResponse : motionReponse;
          _log.severe("Motion asset download failed", failedResponse.toLoggerString());
          return false;

is bad and formats it to

          final failedResponse =
              imageResponse.statusCode != 200 ? imageResponse : motionReponse;
          _log.severe(
              "Motion asset download failed", failedResponse.toLoggerString());
          return false;

(which is less readable from my point of view).
But somehow the linter isn't friends with the formatter and wants to have a final comma:

          final failedResponse =
              imageResponse.statusCode != 200 ? imageResponse : motionReponse;
          _log.severe(
              "Motion asset download failed", failedResponse.toLoggerString(),);
          return false;

The end? No, the formatter wants some changes again:

          final failedResponse =
              imageResponse.statusCode != 200 ? imageResponse : motionReponse;
          _log.severe(
            "Motion asset download failed",
            failedResponse.toLoggerString(),
          );
          return false;

Looks better at least, but it pushed a simply log message from one to four lines and made it seem more important than it needs to be. Similar for the line above that. I thought the formatter is supposed to improve readability but, the 80 character limit achieves the opposite in my eyes (literally 😁).

OK. Rant over, Dart seems to be happy now, so hopefully ready to merge. 😉