hotfix: re-introduced missing AppException throw, updated institution…

…_not_found error with new http status code

src/main/java/it/gov/pagopa/payment/notice/generator/controller/NoticeGenerationController.java

@@ -54,6 +54,8 @@ public ResponseEntity<Resource> generateNotice(@RequestParam(value = "folderId",
             HttpHeaders headers = new HttpHeaders();
             headers.add(HttpHeaders.CONTENT_DISPOSITION, "attachment; filename=\"" + file.getName() + "\"");
             return ResponseEntity.ok().contentType(MediaType.APPLICATION_OCTET_STREAM).headers(headers).body(new ByteArrayResource(inputStream.readAllBytes()));
+        } catch (AppException e) {
+            throw e;
         } catch (Exception e) {
             throw new AppException(AppError.INTERNAL_SERVER_ERROR, e);
         } finally {