Fix(accessibility) fix sa11y accessibility issue for popovers (#5143)

* Fixed Aria label attr

* cleaning code

* cleaning code

* Fixed the release number

* Updated release notes

* removed unreachable null

* removed fallback aria label

* Updated the release note

* changed title

---------

Co-authored-by: Manjunath Kalburgi <[email protected]>

Author: norvinder

ui/components/popovers/RELEASENOTES.md

@@ -5,6 +5,10 @@
 
 ### Added button to the story `body-max-height-small` to fix scrollable-region-focusable wcag issue.
 
+### Added
+
+- Added `title` attribute to meet accessibility requirements.
+
 ## 2.19
 
 ### Fixed

ui/components/popovers/base/example.jsx

@@ -415,7 +415,7 @@ export let examples = [
     id: 'dark-base',
     label: 'Base [dark]',
     element: (
-      <Popover className="slds-popover_dark slds-nubbin_left" closeButton>
+      <Popover className="slds-popover_dark slds-nubbin_left" title="Popover Title" closeButton>
         <p>
           Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do
           eiusmod tempor incididunt ut labore et dolore magna aliqua.