Pin SystemUI-tests to Kotlin 1.9

SystemUI-tests fails to compile with Kotlin 2.0. Various
fixes can be made, but I leave it to the team to decided when and how
those fixes should be applied.

Kotlin 2 is not the current default in Android, but we are very
close.

Bug: 383569207
Flag: EXEMPT unflaggable
Test: m SystemUI-tests
Change-Id: Ia741ba99cf702c2ac61e70d852c34b31b60a9f3b