Improve exception handling in startCallableProcessing

Absorb any exception from the submission to the executor. It will be
handled in the resulting ASYNC dispatch.

Closes gh-30232

spring-web/src/main/java/org/springframework/web/context/request/async/WebAsyncManager.java

@@ -22,7 +22,6 @@ import java.util.List;
 import java.util.Map;
 import java.util.concurrent.Callable;
 import java.util.concurrent.Future;
-import java.util.concurrent.RejectedExecutionException;
 
 import jakarta.servlet.http.HttpServletRequest;
 import org.apache.commons.logging.Log;
@@ -344,10 +343,9 @@ public final class WebAsyncManager {
 			});
 			interceptorChain.setTaskFuture(future);
 		}
-		catch (RejectedExecutionException ex) {
+		catch (Throwable ex) {
 			Object result = interceptorChain.applyPostProcess(this.asyncWebRequest, callable, ex);
 			setConcurrentResultAndDispatch(result);
-			throw ex;
 		}
 	}