Mouse click coords show odd values for text coordinates when clicking in the padding area outside the main map region #72

Describe the bug
If alt-clicking with the mouse to show the map coordinate outside the map region but inside the padding area on the left and top sides of the map, where the coordinates would be expected to have negative values, the text coordinates show unusual characters.

To Reproduce
Steps to reproduce the behavior:

1. Set a square grid map to show letters for both dimensions
2. Make sure the map has a padding zone
3. Alt-click in the padding to either the top or left side of the map
4. See error

Expected behavior
The mouse click coordinates should not display when clicking in the padding zone. This will match the overlay coordinates which don't indicate padding regions.

Foundry Information:

All supported Foundry versions.
All browsers.