TBR: playground: Remove .v23 from all .gitignore files.
TBR: playground: Remove .v23 from all .gitignore files.

MultiPart: 20/25

Change-Id: I83dac52d1881ac8a93a6ca0b8ebb547e4faeacef

vanadium/playground,vanadium/playground,vanadium/playground,vanadium/playground