Change default to require licenses property.

Please do not roll back.

If you have recently created a new Soong module type, please make sure
it supports the `licenses` property.

If your build on an older branch fails due to this change, please
configure your build to set `ANDROID_REQUIRE_LICENSES=false` in the
environment.

If running from the command line, the following will work:

export ANDROID_REQUIRE_LICENSES=false; m -j ...

Previously defaulted to not require property unless overridden in env.

Bug: 151177513

Test: m all

Change-Id: Ib295658f978511d07197c295f04a6f25f7d83686