Upgrade Servlet, JSP and WebSocket API versions

This commit updates the Spring Framework baseline for the Servlet, JSP
and WebSocket APIs.
This also removes the previously deprecated APIs in JSP `PageContext`
and guards against the deprecation of the `PushBuilder` API.

See gh-33918

spring-test/src/main/java/org/springframework/mock/web/MockPageContext.java

@@ -267,26 +267,12 @@ public class MockPageContext extends PageContext {
 		return this.out;
 	}
 
-	@Override
-	@Deprecated
-	@Nullable
-	public jakarta.servlet.jsp.el.ExpressionEvaluator getExpressionEvaluator() {
-		return null;
-	}
-
 	@Override
 	@Nullable
 	public ELContext getELContext() {
 		return null;
 	}
 
-	@Override
-	@Deprecated
-	@Nullable
-	public jakarta.servlet.jsp.el.VariableResolver getVariableResolver() {
-		return null;
-	}
-
 	@Override
 	public HttpSession getSession() {
 		return this.request.getSession();