Set EAP billing event to one-year period

This is consistent with how we treat RESTORE billing events as well- in
general, fees are considered to be amortized over the course of a year (by the
invoicing team).

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=199684843

javatests/google/registry/flows/EppLifecycleDomainTest.java

@@ -305,6 +305,7 @@ public class EppLifecycleDomainTest extends EppTestCase {
             .setReason(Reason.FEE_EARLY_ACCESS)
             .setTargetId("example.tld")
             .setClientId("NewRegistrar")
+            .setPeriodYears(1)
             .setCost(Money.parse("USD 100.00"))
             .setEventTime(createTime)
             .setBillingTime(createTime.plus(Registry.get("tld").getRenewGracePeriodLength()))