Field picker on gadgets are not showing duplicated fields

Issue Summary

If you have two custom fields with the same name, when typing the name of the Custom Field, the Field Picker used on gadgets like Pie Chart, Issue Statistics or Two Dimensional Field Statistics will only show and let you select one of the custom fields.
A common situation is when a custom field called "Team" was created.
This field is a system field used also by "Advanced Roadmap".

Previous versions as 8.20.2 did show both fields on the select list.

This is reproducible on Data Center: (yes) / (no)
 

Steps to Reproduce

1. Using Jira version 8.20.14
2. Create a custom field "Team", add it to some screens and populate some issues with content;
3. Create a dashboard and add the gadgets "Pie Chart", "Issue Statistics" and "Two Dimensional Field Statistics"
4. Select the field "Team" created

Expected Results

Two Custom Fields are presented, one is the System Field, and the other is the Customer field created;
Pick the custom field and observe the graph results.

Actual Results

Only one value was presented;
Selecting this value did not show the expected results as it used the other "Team" from Advanced Roadmap.

Workaround

Using Inspector, we can observe that both Custom Field "Team" are available in the Selection list.

Before Jira 9.4.0:
When clicking on the Selection list to show all the list, the scroll should show both fields in the list however due to JSWSERVER-21360 - Scrolling through options for the field Statistic Type in gadgets is not possible anymore, it was not possible to scroll the full list.
As a workaround, zoom out the page to show more options.

After Jira 9.4.0:
Do not type the name of the field, hit the dropdown arrow to select the field from the list presented, scrolling through the options.