[Discover] [Dataset Quality] Stringify ignored values before rendering (

elastic#203312)

This json-stringifies the values of the `_ignored` fields in the
"quality issues" section of the "logs overview" tab. The tab is shown in
Discover when the space is an "Observability" space or the serverless
project is an "Observability" project and the document is a log entry
document.

Co-authored-by: Elastic Machine <[email protected]>
(cherry picked from commit 38f30a9)

src/plugins/unified_doc_viewer/public/components/doc_viewer_logs_overview/logs_overview_degraded_fields.tsx

@@ -228,7 +228,7 @@ const getDegradedFieldsColumns = (): Array<EuiBasicTableColumn<DegradedField>> =
     sortable: true,
     field: 'values',
     render: (values: string[]) => {
-      return values.map((value, idx) => <EuiBadge key={idx}>{value}</EuiBadge>);
+      return values.map((value, idx) => <EuiBadge key={idx}>{JSON.stringify(value)}</EuiBadge>);
     },
   },
 ];