Harmonize Solr status health details

This commit renames the `solrStatus` property of the Solr health indicator
to `status` and its type. This is now an integer corresponding to the
status Solr sent rather than a String that can be "OK" when all is well.

Closes gh-8878

spring-boot-actuator/src/main/java/org/springframework/boot/actuate/health/SolrHealthIndicator.java

@@ -43,8 +43,7 @@ public class SolrHealthIndicator extends AbstractHealthIndicator {
 		CoreAdminResponse response = request.process(this.solrClient);
 		int statusCode = response.getStatus();
 		Status status = (statusCode == 0 ? Status.UP : Status.DOWN);
-		builder.status(status).withDetail("solrStatus",
-				(statusCode == 0 ? "OK" : statusCode));
+		builder.status(status).withDetail("status", statusCode);
 	}
 
 }

spring-boot-actuator/src/test/java/org/springframework/boot/actuate/health/SolrHealthIndicatorTests.java

@@ -72,7 +72,7 @@ public class SolrHealthIndicatorTests {
 		SolrHealthIndicator healthIndicator = new SolrHealthIndicator(solrClient);
 		Health health = healthIndicator.health();
 		assertThat(health.getStatus()).isEqualTo(Status.UP);
-		assertThat(health.getDetails().get("solrStatus")).isEqualTo("OK");
+		assertThat(health.getDetails().get("status")).isEqualTo(0);
 	}
 
 	@Test
@@ -83,7 +83,7 @@ public class SolrHealthIndicatorTests {
 		SolrHealthIndicator healthIndicator = new SolrHealthIndicator(solrClient);
 		Health health = healthIndicator.health();
 		assertThat(health.getStatus()).isEqualTo(Status.DOWN);
-		assertThat(health.getDetails().get("solrStatus")).isEqualTo(400);
+		assertThat(health.getDetails().get("status")).isEqualTo(400);
 	}
 
 	@Test