[UnifiedSearch] Fix query input styles (#157010)

A follow up for
https://github.com/elastic/kibana/pull/155208/files#diff-6331d8fd9ae662adcdd1491f21ace3925cc950118c13ec7c845c03557e02b2dbR837

## Summary

Before:
<img width="500" alt="Screenshot 2023-05-08 at 17 13 42"
src="https://user-images.githubusercontent.com/1415710/236862658-8b1f4935-ebea-4d45-b14b-37985a28bcaa.png">


After:
<img width="500" alt="Screenshot 2023-05-08 at 17 13 27"
src="https://user-images.githubusercontent.com/1415710/236862033-1f06d436-d03a-45d8-914f-90e9b4efe1c1.png">

src/plugins/unified_search/public/query_string_input/query_string_input.tsx

@@ -843,7 +843,7 @@ export default class QueryStringInputUI extends PureComponent<QueryStringInputPr
                 </div>
               ) : null}
               {this.props.isClearable && !this.props.isDisabled && this.props.query.query ? (
-                <div className="euiFormControlLayoutIcons euiFormControlLayoutIcons--right">
+                <div className="euiFormControlLayoutIcons euiFormControlLayoutIcons--absolute euiFormControlLayoutIcons--right">
                   <button
                     type="button"
                     className="euiFormControlLayoutClearButton"