Fix wrong uri tag for client observation convention

Prior to this commit, a client sending a request to
"https://example.org" would record the wrong URI tag as
"/https://example.org".

This commit ensures that the scheme+host part is matched correctly in
the default client observation conventions.

See gh-33867

spring-web/src/main/java/org/springframework/http/client/observation/DefaultClientRequestObservationConvention.java

@@ -43,7 +43,7 @@ public class DefaultClientRequestObservationConvention implements ClientRequestO
 
 	private static final String DEFAULT_NAME = "http.client.requests";
 
-	private static final Pattern PATTERN_BEFORE_PATH = Pattern.compile("^https?://[^/]+/");
+	private static final Pattern PATTERN_BEFORE_PATH = Pattern.compile("^https?://[^/]+/?");
 
 	private static final KeyValue URI_NONE = KeyValue.of(LowCardinalityKeyNames.URI, KeyValue.NONE_VALUE);
 

spring-webflux/src/main/java/org/springframework/web/reactive/function/client/DefaultClientRequestObservationConvention.java

@@ -43,7 +43,7 @@ public class DefaultClientRequestObservationConvention implements ClientRequestO
 
 	private static final String ROOT_PATH = "/";
 
-	private static final Pattern PATTERN_BEFORE_PATH = Pattern.compile("^https?://[^/]+/");
+	private static final Pattern PATTERN_BEFORE_PATH = Pattern.compile("^https?://[^/]+/?");
 
 	private static final KeyValue URI_NONE = KeyValue.of(LowCardinalityKeyNames.URI, KeyValue.NONE_VALUE);