Create an Android Lint rule to prevent creation of log enforcement vars

The Bluetooth stack sets a process default log level, which allows the
Log framework to properly enforce our log level. Creating log
enforcement variables is unnecessary, as their usage is as well.

Tag: #feature
Bug: 315046089
Flag: EXEMPT, tooling change
Test: atest BluetoothLintCheckerTest --host
Change-Id: I4fdd1c4239294bc07f4d49457cd714899e3294d7