Do not resample when frameTime is not available

LegacyResampler still resamples MotionEvents even when requestedFrameTime is
std::nullopt. The problem is that if the parameter requestedFrameTime
is std::nullopt, it is reassigned inside consumeBatchedInputEvents to
std::numeric_limits<nsecs_t>::max(). In spite of using max() as a
placeholder to indicate that everything should be consumed, it is still a valid time, and resampler uses it to resample MotionEvent. To fix this issue, having a valid requestedFrameTime should also be a condition to resample MotionEvents.

Bug: 374375203
Flag: EXEMPT refactor
Test: TEST=libinput_tests; m $TEST && $ANDROID_HOST_OUT/nativetest64/$TEST/$TEST
Change-Id: I6e53bdd0a35d359da8b50f10dd4aad9bddc8aa3f