Fix an exception when recipe-hovering with a pathological configuration.

[DaleStan]

Specifically, an ArgumentOutOfRangeException happens when hovering over a recipe that is unlocked by a technology that (directly or indirectly) requires a science pack that is both (a) inaccessible and (b) not a milestone.

For an example of this in action, load this vanilla project and hover over either of the two personal roboport recipe icons. Both will cause an exception, but the steel recipe icon won't. Open the milestones editor and add Chemical science pack to the milestones. Alternatively, open the Dependency explorer for the Chemical science pack item, and click "Clear mark". In both cases, the exceptions will disappear.

[shpaass]

Open the milestones editor and add Chemical science pack to the milestones. Alternatively, open the Dependency explorer for the Chemical science pack item, and click "Clear mark". In both cases, the exceptions will disappear.

Without the patch, in the first case, the leftmost icons in the Recipe column still give an exception. The second case removes all errors on hover in the example.

[shpaass]

Without the patch, in the first case, the leftmost icons in the Recipe column still give an exception.

With the proposed PR, this error is still present.

[DaleStan]

I can't reproduce your experience. Are you adding the item, the recipe, or the technology to the milestones? The error depends on the item being missing from the milestones.

I see this:

[shpaass]

Apologies, it was my mistake. I've fetched the PR, but failed to checkout it. The fix works.