storage: Defer blkio class configuration

Move blkio class configuration from on init to on property:sys.boot_completed=1.
This improves I/O balance between foreground and background processes during boot,
as many background processes compete for I/O resources at that time.
Deferring the configuration ensures a smoother user experience
by prioritizing foreground processes.

Bug: 364960533
Test: forrest build and test on felix
Change-Id: If15343d4d96d55032618a4611bf9fdf47105c974
1 file changed