Change the default scaling mode in BLASTBufferQueue to FREEZE

When BLASTBufferQueue size is updated, we update the destination frame
based on the previous buffer's scaling mode. If no buffer has been
submitted, the default scaling mode is
`NATIVE_WINDOW_SCALING_MODE_SCALE_TO_WINDOW` and the destination frame
will be updated to the new size. If the first buffer is not submitted by
BLASTBufferQueue (because its a sync transaction) then an incorrect
scaling mode can be set. To fix this change the default scaling mode to
freeze.

This should have no effect on other graphic producers since the
destination mode is not set by BLASTBufferQueue.

Bug: 435757017
Flag: com.android.graphics.libgui.flags.default_scaling_mode_freeze
Test: presubmit
Change-Id: I2880cf83b41e6c420609a0eb144b1a7b2f9c3433