silence warning about missing ToolsRegistry tool

This should fix: ATLASRECTS-5413

I really did just the minimal thing to silence this warning, but if you ask me this seems not like a happy/healthy design. I'm already far from convinced (to put it mildly) that it is a good idea for analysis code to talk to the ToolStore directly, but for code running in reconstruction to talk to the ASG ToolStore to figure out if a tool exists and if not to create it backhandedly without ever interacting with the ToolSvc at all, well that seems less than ideal, or at the very least somewhat unusual.

I don't know if we have a list of places in which code uses public tools, but obviously those hidden tools are effectively public tools, and as such this whole package should probably be added to that list.