Move @PolicyDefinition inside the type specific one

Since @PolicyDefinition is a base for all type specific policy
definition, unconditionally include it into them. Updated all processing
to take this into account.

Bug: 442557445
Test: atest frameworks/base/tools/processors/devicepolicy/test/src/android/processor/devicepolicy/test/PolicyProcessorTest.kt
Flag: android.app.admin.flags.policy_streamlining
Change-Id: Ie026a371dc07778a2646ae15a3661d8dd806f8a4