audio: Update common types to better match legacy structs

HAL V7 types were updated to better match data structure
definitions from the legacy HAL:

 - Added 'AudioConfigBaseOptional' struct to match
   legacy structs that have 'mask' field to specify
   initialized fields.

 - All fields in 'AudioConfigBase' made mandatory.

 - Removed 'EffectConfigParameters' in favor of
   'AudioConfigBaseOptional' and safe_unions.

 - Added missing enum string values to ensure that round-trip
   conversions from the legacy HAL to HIDL and back to legacy
   preserve enum values.

Bug: 142480271
Test: atest android.hardware.audio.common@7.0-util_tests
Test: atest VtsHalAudioV6_0TargetTest
Test: atest VtsHalAudioV7_0TargetTest
Test: atest VtsHalAudioEffectV7_0TargetTest
Change-Id: If02a81b3f6790a8eb315fa57123141aad2419132