Fix total_score_without_mods population failing if beatmap was deleted

[peppy]

There are cases where scores are in the scores table for deleted beatmaps. This can happen when the beatmap creator submits a new version of a beatmap and causes the old one to be completely nuked from the table. From what I can tell, this is the only case that soft deletion is not a thing for the beatmaps table.

For such scores we don't really have a recover method, so let's just leave them in a state without this field.

Relevant failure:

Processed up to 2315947751 (9560059 backfilled)
Processed up to 2315952751 (9560457 backfilled)
Processed up to 2315957751 (9560911 backfilled)
Unhandled exception. System.Collections.Generic.KeyNotFoundException: The given key '2283259' was not present in the dictionary.
   at osu.Server.Queues.ScoreStatisticsProcessor.Commands.Maintenance.PopulateTotalScoreWithoutModsCommand.OnExecuteAsync(CancellationToken cancellationToken) in /app/osu-queue-score-statistics/osu.Server.Queues.ScoreStatisticsProcessor/Commands/Maintenance/PopulateTotalScoreWithoutModsCommand.cs:line 84
   at McMaster.Extensions.CommandLineUtils.SourceGeneration.ReflectionExecuteHandler.InvokeAsyncMethod(Object instance, Object[] arguments)
   at McMaster.Extensions.CommandLineUtils.SourceGeneration.ReflectionExecuteHandler.InvokeAsync(Object model, CommandLineApplication app, CancellationToken cancellationToken)
   at McMaster.Extensions.CommandLineUtils.Conventions.ExecuteMethodConvention.<>c__DisplayClass0_0.<<Apply>b__1>d.MoveNext()
--- End of stack trace from previous location ---
   at McMaster.Extensions.CommandLineUtils.CommandLineApplication.ExecuteAsync(String[] args, CancellationToken cancellationToken)
   at McMaster.Extensions.CommandLineUtils.CommandLineApplication.ExecuteAsync[TApp](CommandLineContext context, CancellationToken cancellationToken)
   at osu.Server.Queues.ScoreStatisticsProcessor.Program.Main(String[] args) in /app/osu-queue-score-statistics/osu.Server.Queues.ScoreStatisticsProcessor/Program.cs:line 27
   at osu.Server.Queues.ScoreStatisticsProcessor.Program.<Main>(String[] args)

[bdach]

Skipping is fine in the immediate term but something - whether it be setting ranked to zero or whatever else - is going to have to be done later to accommodate for this not actually being universally present e.g. in the command in #269, so that it knows to skip these rows.

Not sure what your plan on that is.

[peppy]

I think that command would probably be best skip rows with the value missing regardless.

Though having an assertion that the without_multipliers is always present may simplify things in the future, so I can work with that in mind if you think it's best.

[peppy]

Either way, I think let's get this in and do an initial pass then see how many scores remain in a bad state?