Add base64 and csv gems to Gemfile #27665

Job	Run time
syntax	48s
formula audit	6m 2s
vendored gems	40s
docker	4m 30s
cask audit	5m 15s
tap syntax	4m 44s
test default formula (Ubuntu 22.04)	1m 26s
tests (online)	8m 42s
update-test (Ubuntu 22.04)	31s
test default formula (Ubuntu 20.04)	1m 26s
tests (generic OS)	6m 4s
update-test (macOS 13)	1m 20s
test default formula (macOS 13 x86_64)	1m 21s
tests (Ubuntu 22.04)	5m 48s
test default formula (macOS 14 arm64)	1m 25s
tests (Ubuntu 20.04)	6m 47s
tests (macOS 13 x86_64)	8m 0s
tests (macOS 14 arm64)	5m 2s
	1h 9m 51s

Provide feedback