[ruby/sinatra] Release connection to pool outside block

[p8]

ActiveRecord 7.2 introduced ActiveRecord::Base.with_connection which releases the connection after the block has run. This allows us to remove clearing active connections after the request has finished.

	plaintext	update	json	db	query	fortune	weighted_score
master	73851	7851	84330	37661	15144	19934	1109
branch	83429	8401	91051	41432	14251	21369	1147