Cleanup of not used ImeTracing.getInstance() try-catch block

Inner called function IInputMethodManagerGlobalInvoker.isImeTraceEnabled
already contains RuntimeException.rethrowFromSystemServer() which will
raise an exception rather than returning an empty object.

Test: atest android.view.inputmethod.cts
Fix: 233710165
Change-Id: Ice4aa19c32b3da951be74189d3dda6411591d2a8