adb: Revert "Allow UsbDeviceManager to start adbd again."

This reverts commit 7a380099.

Reason for revert: a proper fix (ag/10420943)
    landed into system/core/init to prevent USB
    configured  as "none/adb" and this workaround
    is no longer required.

Bug: 402444824
Flag: EXEMPT cleanup
Test: flashed a recent Pixel device with both
    user and userdebug builds, booted,
    enabled USB debugging, rebooted and
    checked that `adb shell` still works.
Change-Id: Idaa167940c6e5eab252b051c4ab0b35fe2ac3edd
Signed-off-by: Roman Kiryanov <rkir@google.com>