Fix initial Eureka instance replication delay

[yashdotdev13]

Overview

Fixes an issue where the initial Eureka instance status update can trigger an
on-demand registration before the configured initial instance info replication
delay has elapsed.

Changes

• Set the initial Eureka instance status before initializing the Eureka client.
• Prevent the initial status change from triggering an immediate on-demand
  registration.
• Added a regression test to verify that the initial status is set before
  Eureka client initialization.

Testing

• ./mvnw.cmd -pl spring-cloud-netflix-eureka-client -Dtest=EurekaServiceRegistryTests test
• ./mvnw.cmd -pl spring-cloud-netflix-eureka-client test

Results:

• EurekaServiceRegistryTests: 6/6 passed
• Eureka client module: 211/211 passed
• Checkstyle: 0 violations

Related Issue

Fixes #4109