When null is provided as a deferred configuration, continue with the …

…current configuration (#3602)

Signed-off-by: Violeta Georgieva <[email protected]>

reactor-netty-http/src/main/java/reactor/netty/http/client/HttpClient.java

@@ -625,7 +625,7 @@ public final HttpClient cookiesWhen(String name, Function<? super Cookie, Mono<?
 		HttpClient dup = duplicate();
 		dup.configuration().deferredConf(config -> {
 			Mono<? extends Cookie> mono = cookieBuilder.apply(new DefaultCookie(name, ""));
-			return mono == Mono.<Cookie>empty() ?
+			return mono == null || mono == Mono.<Cookie>empty() ?
 					Mono.just(config) :
 					mono.map(c -> {
 						if (!c.value().isEmpty()) {
@@ -1061,7 +1061,7 @@ public final HttpClient headersWhen(Function<? super HttpHeaders, Mono<? extends
 		HttpClient dup = duplicate();
 		dup.configuration().deferredConf(config -> {
 			Mono<? extends HttpHeaders> mono = headerBuilder.apply(config.headers.copy());
-			return mono == Mono.<HttpHeaders>empty() ?
+			return mono == null || mono == Mono.<HttpHeaders>empty() ?
 					Mono.just(config) :
 					mono.map(h -> {
 						config.headers = h;