Constant timer ticks in v1.23 and later

[lhecker]

Windows Terminal version

1.23.10353.0

Windows build number

No response

Other Software

No response

Steps to reproduce

• Open a dozen or a couple dozen tabs
• Observe constant CPU usage (in something better than Task Manager)

Expected Behavior

0 idle CPU usage, aside from WinUI doing WinUI things (thanks WinUI).

Actual Behavior

Roughly 0.01% CPU usage per 5 tabs. Not much, but bad for battery.

[zadjii-msft]

Isn't this the "stop blinking the cursor" thing? #5318

[lhecker]

No, this also happens if the window is in the background. It must be a recent regression.