[8.x] [Obs Alerts table] Fix error on clicking alert reason message (e…

…lastic#193693) (elastic#193718)

# Backport

This will backport the following commits from `main` to `8.x`:
- [[Obs Alerts table] Fix error on clicking alert reason message
(elastic#193693)](elastic#193693)

<!--- Backport version: 9.4.3 -->

### Questions ?
Please refer to the [Backport tool
documentation](https://github.com/sqren/backport)

<!--BACKPORT [{"author":{"name":"Bena
Kansara","email":"69037875+benakansara@users.noreply.github.com"},"sourceCommit":{"committedDate":"2024-09-23T13:08:15Z","message":"[Obs
Alerts table] Fix error on clicking alert reason message
(elastic#193693)\n\nResolves
https://github.com/elastic/kibana/issues/193692","sha":"2304fb67365325bfcb530d3fa2a658544d8a7016","branchLabelMapping":{"^v9.0.0$":"main","^v8.16.0$":"8.x","^v(\\d+).(\\d+).\\d+$":"$1.$2"}},"sourcePullRequest":{"labels":["release_note:skip","v9.0.0","ci:project-deploy-observability","Team:obs-ux-management","v8.16.0","backport:version"],"title":"[Obs
Alerts table] Fix error on clicking alert reason
message","number":193693,"url":"https://github.com/elastic/kibana/pull/193693","mergeCommit":{"message":"[Obs
Alerts table] Fix error on clicking alert reason message
(elastic#193693)\n\nResolves
https://github.com/elastic/kibana/issues/193692","sha":"2304fb67365325bfcb530d3fa2a658544d8a7016"}},"sourceBranch":"main","suggestedTargetBranches":["8.x"],"targetPullRequestStates":[{"branch":"main","label":"v9.0.0","branchLabelMappingKey":"^v9.0.0$","isSourceBranch":true,"state":"MERGED","url":"https://github.com/elastic/kibana/pull/193693","number":193693,"mergeCommit":{"message":"[Obs
Alerts table] Fix error on clicking alert reason message
(elastic#193693)\n\nResolves
https://github.com/elastic/kibana/issues/193692","sha":"2304fb67365325bfcb530d3fa2a658544d8a7016"}},{"branch":"8.x","label":"v8.16.0","branchLabelMappingKey":"^v8.16.0$","isSourceBranch":false,"state":"NOT_CREATED"}]}]
BACKPORT-->

Co-authored-by: Bena Kansara <69037875+benakansara@users.noreply.github.com>

x-pack/plugins/observability_solution/observability/public/components/alert_overview/helpers/map_rules_params_with_flyout.ts

@@ -89,7 +89,9 @@ export const mapRuleParamsWithFlyout = (alert: TopAlert): FlyoutThresholdData[]
   switch (ruleId) {
     case OBSERVABILITY_THRESHOLD_RULE_TYPE_ID:
       return observedValues.map((observedValue, metricIndex) => {
-        const criteria = ruleCriteria[metricIndex] as CustomMetricExpressionParams;
+        const criteria = Array.isArray(ruleCriteria)
+          ? (ruleCriteria[metricIndex] as CustomMetricExpressionParams)
+          : (ruleCriteria as CustomMetricExpressionParams);
         const fields = criteria.metrics.map((metric) => metric.field || 'COUNT_AGG');
         const comparator = criteria.comparator;
         const threshold = criteria.threshold;
@@ -118,12 +120,20 @@ export const mapRuleParamsWithFlyout = (alert: TopAlert): FlyoutThresholdData[]
 
     case METRIC_THRESHOLD_ALERT_TYPE_ID:
       return observedValues.map((observedValue, metricIndex) => {
-        const criteria = ruleCriteria[metricIndex] as BaseMetricExpressionParams & {
-          metric: string;
-          customMetrics: Array<{
-            field?: string;
-          }>;
-        };
+        const criteria = Array.isArray(ruleCriteria)
+          ? (ruleCriteria[metricIndex] as BaseMetricExpressionParams & {
+              metric: string;
+              customMetrics: Array<{
+                field?: string;
+              }>;
+            })
+          : (ruleCriteria as BaseMetricExpressionParams & {
+              metric: string;
+              customMetrics: Array<{
+                field?: string;
+              }>;
+            });
+
         let fields: string[] = [];
         const metric = criteria.metric;
         const customMetric = criteria.customMetrics;
@@ -157,14 +167,21 @@ export const mapRuleParamsWithFlyout = (alert: TopAlert): FlyoutThresholdData[]
 
     case METRIC_INVENTORY_THRESHOLD_ALERT_TYPE_ID:
       return observedValues.map((observedValue, metricIndex) => {
-        const { threshold, customMetric, metric, comparator } = ruleCriteria[
-          metricIndex
-        ] as BaseMetricExpressionParams & {
-          metric: string;
-          customMetric: {
-            field: string;
-          };
-        };
+        const criteria = Array.isArray(ruleCriteria)
+          ? (ruleCriteria[metricIndex] as BaseMetricExpressionParams & {
+              metric: string;
+              customMetric: {
+                field: string;
+              };
+            })
+          : (ruleCriteria as BaseMetricExpressionParams & {
+              metric: string;
+              customMetric: {
+                field: string;
+              };
+            });
+
+        const { threshold, customMetric, metric, comparator } = criteria;
         const metricField = customMetric?.field || metric;
         const thresholdFormatted = threshold.map((thresholdToFormat) => {
           if (