config properties support for spring starter clients

instrumentation/spring/spring-boot-autoconfigure-3/src/main/java/io/opentelemetry/instrumentation/spring/autoconfigure/instrumentation/web/RestClientBeanPostProcessor.java

@@ -57,7 +57,7 @@ private static RestClient addRestClientInterceptorIfNotPresent(
   static ClientHttpRequestInterceptor getInterceptor(
       OpenTelemetry openTelemetry, ConfigProperties config) {
     return InstrumentationConfigUtil.configureBuilder(
-            config, SpringWebTelemetry.builder(openTelemetry), WebTelemetryUtil.GET_BUILDER)
+            config, SpringWebTelemetry.builder(openTelemetry), WebTelemetryUtil.getBuilder())
         .build()
         .newInterceptor();
   }

instrumentation/spring/spring-boot-autoconfigure/src/main/java/io/opentelemetry/instrumentation/spring/autoconfigure/instrumentation/web/RestTemplateInstrumentation.java

@@ -25,7 +25,7 @@ static RestTemplate addIfNotPresent(
 
     ClientHttpRequestInterceptor instrumentationInterceptor =
         InstrumentationConfigUtil.configureBuilder(
-                config, SpringWebTelemetry.builder(openTelemetry), WebTelemetryUtil.GET_BUILDER)
+                config, SpringWebTelemetry.builder(openTelemetry), WebTelemetryUtil.getBuilder())
             .build()
             .newInterceptor();
 

instrumentation/spring/spring-web/spring-web-3.1/library/src/main/java/io/opentelemetry/instrumentation/spring/web/v3_1/SpringWebTelemetryBuilder.java

@@ -24,7 +24,7 @@ public final class SpringWebTelemetryBuilder {
   private final DefaultHttpClientInstrumenterBuilder<HttpRequest, ClientHttpResponse> builder;
 
   static {
-    WebTelemetryUtil.GET_BUILDER = SpringWebTelemetryBuilder::getBuilder;
+    WebTelemetryUtil.setGetBuilder(SpringWebTelemetryBuilder::getBuilder);
   }
 
   SpringWebTelemetryBuilder(OpenTelemetry openTelemetry) {

instrumentation/spring/spring-web/spring-web-3.1/library/src/main/java/io/opentelemetry/instrumentation/spring/web/v3_1/internal/WebTelemetryUtil.java

@@ -19,9 +19,23 @@ public class WebTelemetryUtil {
   private WebTelemetryUtil() {}
 
   // allows access to the private field for the spring starter
-  @SuppressWarnings("ConstantField")
+  private static Function<
+          SpringWebTelemetryBuilder,
+          DefaultHttpClientInstrumenterBuilder<HttpRequest, ClientHttpResponse>>
+      getBuilder;
+
   public static Function<
           SpringWebTelemetryBuilder,
           DefaultHttpClientInstrumenterBuilder<HttpRequest, ClientHttpResponse>>
-      GET_BUILDER;
+      getBuilder() {
+    return getBuilder;
+  }
+
+  public static void setGetBuilder(
+      Function<
+              SpringWebTelemetryBuilder,
+              DefaultHttpClientInstrumenterBuilder<HttpRequest, ClientHttpResponse>>
+          getBuilder) {
+    WebTelemetryUtil.getBuilder = getBuilder;
+  }
 }