Support DatabaseInitializerDetector ordering

Update `DatabaseInitializationDependencyConfigurer` so that depends-on
ordering is applied based on the `DatabaseInitializerDetector` order.

Prior to this commit, if multiple DatabaseInitializer beans were
detected the order in which they were initialized was not defined.

See gh-26692

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/flyway/FlywayMigrationInitializerDatabaseInitializerDetector.java

@@ -34,4 +34,9 @@ class FlywayMigrationInitializerDatabaseInitializerDetector extends AbstractBean
 		return Collections.singleton(FlywayMigrationInitializer.class);
 	}
 
+	@Override
+	public int getOrder() {
+		return 1;
+	}
+
 }