Condition background record restriction on Sdk

To prevent breaking existing apps, modify the checks around when
an app should have its recording silenced to retain prior behavior
unless an app has targetSdk U or greater.

Test: oboetester conditionally restricted based on targetSdk level
Bug: 268724205
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:dc4f375d570965775634d90856719b812aee9865)
Merged-In: I42b6cbca60db6ce1a073254239b48e9104c4ebfb
Change-Id: I42b6cbca60db6ce1a073254239b48e9104c4ebfb