refactor(magnification): refactor window magnification onRectangleOnScreenRequested tests

Split the onRectangleOnScreenRequested tests into two parts. One is for
verifying the trackingFocusTypingEnabled state, another is for verifying
the window magnification behaviors when onRectangleOnScreenRequested
called.

Bug: 409661124
Flag: EXEMPT refactor tests
Test: atest MagnificationConnectionManagerTest

Change-Id: I607680a16d306417936e27a2eec0672f57f33ad0