[BUG] : Dimensions getting removed when no timeseries field is present

[nidhisinghai]

What is the bug?

1. Dimensions getting removed when no timeseries field is present
2. When changing the PPL or editing the existing query the page gets blank

How can one reproduce the bug?
Steps to reproduce the behavior:

1. Go to observability->Event analytics -> Explorer

2. put a ppl query as
   source=opensearch_dashboards_sample_data_logs | where response='503' or response='404' | stats count() as ip_count, sum(bytes) as sum_bytes by response

3. click Refresh

4. select timeseries for the chart
   here Dimensions gets removed from data configuration panel

5. edit the ppl query for any changes to paste a new ppl query, select another chart from the list
   here the page gets blank and we need to go to some other page apart from observability to make this work again

Issue 1:

Issue 2:

@abasatwar @spattnaik

[nidhisinghai]

closing this as issue resolved