Do not treat Alt-Tab as resolution change
Fixes #7866.
Summary of changes:
- Ignore
SDL_WINDOWEVENT_SIZE_CHANGED
event when OpenMW window is not active (its size is 0x0). Allows to fix validation spam after an every window minimizing. - Do not fire
windowResized
WindowManager's event if window size did not change (happens when you restore the window). Allows to do not reset console when OpenMW window becomes active again.