[Bugfix]:audio fix timestretch logic for playbackcapture screen

timestretch screen for audio playback, Reduce the buffer size
obtained from sharebuffer to the size of mLocalBufferFrameCount
or smaller, to ensure that patchRecord can copy data to patchTrack
in time during playbackcapture to reduce underrun.

Flag: EXEMPT bugfix
Bug: 409640466
Test: https://b.corp.google.com/issues/409640466#comment1



Change-Id: I0ffcf760819c0b243e967e8fd8daae4976e2a92c
Signed-off-by: shiyunpeng <shiyunpeng@xiaomi.corp-partner.google.com>