[Synthetics] Enable Synthetics menu to be searched in the global sear…

…ch bar (#182613)

closes [#181974](#181974)

## Summary

Summarize your PR. If it involves visual changes include a screenshot or
gif.
<img width="1144" alt="image"
src="https://github.com/elastic/kibana/assets/2767137/5d26f562-bf9f-44e4-a9d8-e3d4a2d0e781">

<img width="1148" alt="image"
src="https://github.com/elastic/kibana/assets/2767137/7370fbf2-27fb-4de3-84ff-b2f3ade8ee73">


### How to test
- run `yarn es serverless --projectType=oblt --kill --clean --license
trial -E xpack.security.authc.api_key.enabled=true`
- run `yarn serverless-oblt`
- type Synthetics in the top searchbar
- do the same in stateful

Co-authored-by: Kibana Machine <42973632+kibanamachine@users.noreply.github.com>

x-pack/plugins/observability_solution/synthetics/public/plugin.ts

@@ -159,19 +159,21 @@ export class UptimePlugin
       deepLinks: [
         {
           id: 'overview',
-          title: i18n.translate('xpack.synthetics.overviewPage.linkText', {
-            defaultMessage: 'Monitors',
-          }),
+          title: this._isServerless
+            ? i18n.translate('xpack.synthetics.overviewPage.serverless.linkText', {
+                defaultMessage: 'Overview',
+              })
+            : i18n.translate('xpack.synthetics.overviewPage.linkText', {
+                defaultMessage: 'Monitors',
+              }),
           path: '/',
-          visibleIn: this._isServerless ? ['globalSearch', 'sideNav'] : [],
         },
         {
           id: 'certificates',
           title: i18n.translate('xpack.synthetics.deepLink.certificatesPage.linkText', {
             defaultMessage: 'TLS Certificates',
           }),
           path: '/certificates',
-          visibleIn: this._isServerless ? ['globalSearch', 'sideNav'] : [],
         },
       ],
       mount: async (params: AppMountParameters) => {