This fixes one case of GridCoordinates being used unnecessarily, in
GameScreenBase.
It replaces other cases with explicit calls to TryFindGridAt and
GetDefaultGrid.
* Non-accessed local variable
* Merge cast and type checks.
* StringComparison.Ordinal added for better culture support
* Supposed code improvement in launcher. Remove unused code.
* Update ExplosionHelper.cs
Unintentional change.
* Optimized Import
* Add Robust.Shared.Utility import where it was deleted
* Other random suggestion
* Improve my comment