Polish "Upgrade to Jetty 12.1.0"

See https://github.com/jetty/jetty.project/issues/13483
See gh-46906

module/spring-boot-jetty/src/main/java/org/springframework/boot/jetty/autoconfigure/JettyServerProperties.java

@@ -73,7 +73,7 @@ public class JettyServerProperties {
 	/**
 	 * Maximum size of the HTTP response header.
 	 */
-	private DataSize maxHttpResponseHeaderSize = DataSize.ofKilobytes(8);
+	private DataSize maxHttpResponseHeaderSize = DataSize.ofKilobytes(16);
 
 	/**
 	 * Maximum number of connections that the server accepts and processes at any given

module/spring-boot-jetty/src/test/java/org/springframework/boot/jetty/autoconfigure/JettyWebServerFactoryCustomizerTests.java

@@ -288,15 +288,15 @@ class JettyWebServerFactoryCustomizerTests {
 	@Test
 	void defaultMaxHttpResponseHeaderSize() {
 		JettyWebServer server = customizeAndGetServer();
-		List<Integer> responseHeaderSizes = getResponseHeaderSizes(server);
-		assertThat(responseHeaderSizes).containsOnly(8192);
+		List<Integer> responseHeaderSizes = getMaxResponseHeaderSizes(server);
+		assertThat(responseHeaderSizes).containsOnly(16384);
 	}
 
 	@Test
 	void customizeMaxHttpResponseHeaderSize() {
 		bind("server.jetty.max-http-response-header-size=2KB");
 		JettyWebServer server = customizeAndGetServer();
-		List<Integer> responseHeaderSizes = getResponseHeaderSizes(server);
+		List<Integer> responseHeaderSizes = getMaxResponseHeaderSizes(server);
 		assertThat(responseHeaderSizes).containsOnly(2048);
 	}
 
@@ -304,16 +304,16 @@ class JettyWebServerFactoryCustomizerTests {
 	void customMaxHttpResponseHeaderSizeIgnoredIfNegative() {
 		bind("server.jetty.max-http-response-header-size=-1");
 		JettyWebServer server = customizeAndGetServer();
-		List<Integer> responseHeaderSizes = getResponseHeaderSizes(server);
-		assertThat(responseHeaderSizes).containsOnly(8192);
+		List<Integer> responseHeaderSizes = getMaxResponseHeaderSizes(server);
+		assertThat(responseHeaderSizes).containsOnly(16384);
 	}
 
 	@Test
 	void customMaxHttpResponseHeaderSizeIgnoredIfZero() {
 		bind("server.jetty.max-http-response-header-size=0");
 		JettyWebServer server = customizeAndGetServer();
-		List<Integer> responseHeaderSizes = getResponseHeaderSizes(server);
-		assertThat(responseHeaderSizes).containsOnly(8192);
+		List<Integer> responseHeaderSizes = getMaxResponseHeaderSizes(server);
+		assertThat(responseHeaderSizes).containsOnly(16384);
 	}
 
 	@Test
@@ -351,8 +351,8 @@ class JettyWebServerFactoryCustomizerTests {
 		return getHeaderSizes(server, HttpConfiguration::getRequestHeaderSize);
 	}
 
-	private List<Integer> getResponseHeaderSizes(JettyWebServer server) {
-		return getHeaderSizes(server, HttpConfiguration::getResponseHeaderSize);
+	private List<Integer> getMaxResponseHeaderSizes(JettyWebServer server) {
+		return getHeaderSizes(server, HttpConfiguration::getMaxResponseHeaderSize);
 	}
 
 	private List<Integer> getHeaderSizes(JettyWebServer server, Function<HttpConfiguration, Integer> provider) {