[Discover] New responsive layout using EUI components (#83633)

Co-authored-by: Andrea Del Rio <delrio.andre@gmail.com>
Co-authored-by: cchaos <caroline.horn@elastic.co>
Co-authored-by: Michail Yasonik <michail.yasonik@elastic.co>
Co-authored-by: Dave Snider <dave.snider@gmail.com>
Co-authored-by: Marta Bondyra <marta.bondyra@elastic.co>

src/plugins/discover/public/application/angular/context/components/action_bar/action_bar.tsx

@@ -119,7 +119,7 @@ export function ActionBar({
             </EuiButtonEmpty>
           </EuiFlexItem>
           <EuiFlexItem grow={false}>
-            <EuiFormRow>
+            <EuiFormRow display="center">
               <EuiFieldNumber
                 aria-label={
                   isSuccessor
@@ -130,6 +130,7 @@ export function ActionBar({
                         defaultMessage: 'Number of newer documents',
                       })
                 }
+                compressed
                 className="cxtSizePicker"
                 data-test-subj={`${type}CountPicker`}
                 disabled={isDisabled}