Excalibur v0.28.7 Release

Bugfix release! This release is slightly different cut from the branch release/v0.28.x instead of main, this is because features that are not ready to ship are in the mainline currently and will be shipped as part of v0.29.0

• fix: Add friendly error if canvasElementId missing(#2885)
• fix: ex.Material no longer does lazy init, requires graphics context
• fix: Issue with pointer events on screen elements (#2902)

Also big thanks to @jyoung4242! This was his first contribution to Excalibur!

Full Changelog: v0.28.6...v0.28.7