ra/ratelimits: Update tests, use new TransactionBuilder constructor, fix ARI rate limit exception #7521

Job	Run time
vendorcheck (1.22.5)	26s
govulncheck	11s
b (go1.23.1_2024-09-05, ./t.sh --lints --generate)	3m 30s
b (go1.23.1_2024-09-05, ./t.sh --integration)	5m 41s
b (go1.23.1_2024-09-05, ./tn.sh --integration)	7m 52s
b (go1.23.1_2024-09-05, ./t.sh --unit --enable-race-detection)	7m 38s
b (go1.23.1_2024-09-05, ./tn.sh --unit --enable-race-detection)	7m 48s
b (go1.23.1_2024-09-05, ./t.sh --start-py)	2m 51s
Boulder CI Test Matrix	1s
	35m 58s

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