Increase default Wm buffer size

Since WM will not be used in the always-on tracing it doesn't need to
have such small buffer sizes. Moreover, the current buffer size don't
record much information (last 10sec max) causing issues when traces are
included in user bugs.

Test: atest FlickerLibTest FlickerTests WMShellFlickerTests
Bug: 207387612
Change-Id: I260435cb5e64279e9d0fe38d5195300e514e18c5