Auction server URI config param in samples

[maciejkowalczyk]

Docs for FLEDGE Java samples say:

1. Set your key value server endpoint

adb shell "device_config put adservices ad_selection_data_auction_key_fetch_uri [your key fetch endpoint uri]"

It seems that the actual config param name is fledge_auction_server_auction_key_fetch_uri (like docs for Java PAS samples suggest)