Fix statsd metrics collection for names with ":"

Statsd server is ignoring malformed metrics. This change introduces
a basic sanitizing to metric names for avoid losing those metrics.

See gh-8906

spring-boot-actuator/src/test/java/org/springframework/boot/actuate/metrics/statsd/StatsdMetricWriterTests.java

@@ -36,6 +36,7 @@ import static org.assertj.core.api.Assertions.assertThat;
  * Tests for {@link StatsdMetricWriter}.
  *
  * @author Dave Syer
+ * @author Odín del Río
  */
 public class StatsdMetricWriterTests {
 
@@ -97,6 +98,20 @@ public class StatsdMetricWriterTests {
 		assertThat(this.server.messagesReceived().get(0)).isEqualTo("my.gauge.foo:3|g");
 	}
 
+	@Test
+	public void incrementMetricWithInvalidCharsInName() throws Exception {
+		this.writer.increment(new Delta<>("counter.fo:o", 3L));
+		this.server.waitForMessage();
+		assertThat(this.server.messagesReceived().get(0)).isEqualTo("me.counter.foo:3|c");
+	}
+
+	@Test
+	public void setMetricWithInvalidCharsInName() throws Exception {
+		this.writer.set(new Metric<>("gauge.f:o:o", 3L));
+		this.server.waitForMessage();
+		assertThat(this.server.messagesReceived().get(0)).isEqualTo("me.gauge.foo:3|g");
+	}
+
 	private static final class DummyStatsDServer implements Runnable {
 
 		private final List<String> messagesReceived = new ArrayList<String>();