Fix NullPointerException in ControlsRequestDialogTest

When the @NonNull and @Nullable annotations are fixed to be class
retention it triggered an NullPointerException in ControlsRequestDialogTest:

08-25 00:58:09.852  1000 23910 23932 E TestRunner: java.lang.NullPointerException: eq(...) must not be null
08-25 00:58:09.852  1000 23910 23932 E TestRunner: 	at com.android.systemui.controls.management.ControlsRequestDialogTest.testDialogAddsCorrectControl(ControlsRequestDialogTest.kt:138)

com.android.systemui.util.mockito.eq should probably be replaced with
org.mockito.kotlin.eq, but for now just copy org.mockito.kotlin.eq
by adding "?: obj".

Bug: 294110802
Test: atest SystemUITests
Change-Id: Ia3a06575fdad99c8fe3811d64a5879d3dabe854e
Merged-In: Ia3a06575fdad99c8fe3811d64a5879d3dabe854e
(cherry picked from commit 00039da3)