iatlasGraphQLClient::query_single_cell_seq_feature_values()` raises an 502 error

[heimannch]

@andrewelamb, the function iatlasGraphQLClient::query_single_cell_seq_feature_values() raises an 502 error.
All other queries associated with single cell data are working fine.

> x <- iatlasGraphQLClient::query_single_cell_seq_feature_values(features = "umap_1")
Error: Bad Gateway (HTTP 502)
16. stop(sprintf("%s (HTTP %s)", x$message, x$status_code), call. = FALSE)
15. res$raise_for_status()
14. gh_POST(self$url, body, self$headers, ...)
13. cont(gh_POST(self$url, body, self$headers, ...), encoding = encoding)
12. ghql_con$exec(query, variables)
11. jsonlite::fromJSON(.)
10. pluck_raw(.x, list2(...), .default = .default)
9. purrr::pluck(., "data")
8. ghql_con$exec(query, variables) %>% jsonlite::fromJSON() %>%
purrr::pluck("data") at api_functions.R#47
7. perform_api_query(query_args, query_file, ...)
6. pluck_raw(.x, list2(...), .default = .default)
5. purrr::pluck(., 1)
4. perform_api_query(query_args, query_file, ...) %>% purrr::pluck(1) at api_functions.R#197
3. do_cursor_paginated_api_query(query_args, query_file, ...) at api_functions.R#144
2. create_result_from_cursor_paginated_api_query(query_args = list(cohort = cohorts,
feature = features, paging = paging, distinct = F), query_file = "single_cell_feature_values.txt",
default_tbl = dplyr::tibble(feature_name = character(), feature_display = character(),
feature_order = integer(), feature_class = character(), ... at api_features_queries.R#192
1. iatlasGraphQLClient::query_single_cell_seq_feature_values(features = "umap_1")

This issue is observed for the staging database, and iatlasGraphQLClient 0.2.6 and 0.2.7

This is an important issue, as it compromises the availability of newer datasets in the web app.