[9.1][a11y] Fix focus on generate API keys in connectors config (elastic#237918)

## Summary

This implements a workaround solution to the one introduced in elastic#237522
since `EuiConfirmModal` doesn't support the `focusTrapProps` prop until
EUI v106.4.0 (currently on `104.0.2`).

The previous attempt at an automated backport for reference: elastic#237722.

### Checklist

Check the PR satisfies following conditions.

Reviewers should verify this PR satisfies this list as well.

- [x] Any text added follows [EUI's writing
guidelines](https://elastic.github.io/eui/#/guidelines/writing), uses
sentence case text and includes [i18n
support](https://github.com/elastic/kibana/blob/main/src/platform/packages/shared/kbn-i18n/README.md)
- [x]
[Documentation](https://www.elastic.co/guide/en/kibana/master/development-documentation.html)
was added for features that require explanation or tutorials
- [x] [Unit or functional
tests](https://www.elastic.co/guide/en/kibana/master/development-tests.html)
were updated or added to match the most common scenarios
- [x] If a plugin configuration key changed, check if it needs to be
allowlisted in the cloud and added to the [docker
list](https://github.com/elastic/kibana/blob/main/src/dev/build/tasks/os_packages/docker_generator/resources/base/bin/kibana-docker)
- [x] This was checked for breaking HTTP API changes, and any breaking
changes have been approved by the breaking-change committee. The
`release_note:breaking` label should be applied in these situations.
- [x] [Flaky Test
Runner](https://ci-stats.kibana.dev/trigger_flaky_test_runner/1) was
used on any tests changed
- [x] The PR description includes the appropriate Release Notes section,
and the correct `release_note:*` label is applied per the
[guidelines](https://www.elastic.co/guide/en/kibana/master/contributing.html#kibana-release-notes-process)
- [x] Review the [backport
guidelines](https://docs.google.com/document/d/1VyN5k91e5OVumlc0Gb9RPa3h1ewuPE705nRtioPiTvY/edit?usp=sharing)
and apply applicable `backport:*` labels.

Co-authored-by: Elastic Machine <elasticmachine@users.noreply.github.com>
(cherry picked from commit 652d68e)

# Conflicts:
#	x-pack/platform/plugins/shared/content_connectors/public/components/connector_detail/components/generated_config_fields.tsx
#	x-pack/solutions/search/plugins/enterprise_search/public/applications/enterprise_search_content/components/connector_detail/components/generated_config_fields.tsx

Author: dennis-tismenko

x-pack/solutions/search/plugins/enterprise_search/public/applications/enterprise_search_content/components/connector_detail/components/generated_config_fields.tsx

@@ -5,7 +5,9 @@
  * 2.0.
  */
 
-import React, { useState } from 'react';
+import React, { useRef, useState } from 'react';
+
+import { defer } from 'lodash';
 
 import {
   EuiButtonIcon,
@@ -83,18 +85,32 @@ export const GeneratedConfigFields: React.FC<GeneratedConfigFieldsProps> = ({
   generateApiKey,
   isGenerateLoading,
 }) => {
+  const apiKeyContainerRef = useRef<HTMLDivElement>(null);
+  const restoreFocusRef = useRef<HTMLElement | null>(null);
   const [isModalVisible, setIsModalVisible] = useState(false);
 
   const refreshButtonClick = () => {
+    restoreFocusRef.current = document.activeElement as HTMLElement;
     setIsModalVisible(true);
   };
+  const restoreFocus = () => {
+    if (!restoreFocusRef.current || (restoreFocusRef.current as HTMLButtonElement).disabled) {
+      apiKeyContainerRef.current?.focus();
+      return;
+    } else {
+      restoreFocusRef.current?.focus();
+    }
+    restoreFocusRef.current = null;
+  };
+
   const onCancel = () => {
     setIsModalVisible(false);
   };
 
   const onConfirm = () => {
     if (generateApiKey) generateApiKey();
     setIsModalVisible(false);
+    defer(restoreFocus);
   };
 
   return (
@@ -223,6 +239,8 @@ export const GeneratedConfigFields: React.FC<GeneratedConfigFieldsProps> = ({
               gutterSize="xs"
               justifyContent="flexEnd"
               alignItems="center"
+              ref={apiKeyContainerRef}
+              tabIndex={-1}
             >
               {apiKey?.encoded ? (
                 <EuiFlexItem>