[SLO] Remove legacy feedback button from SLO (#271688)

Closes elastic/kibana-team#2852

Note: alert details feedback button referenced in the closed issue was
previously removed in #266810

## Summary

Removes the legacy `FeedbackButton` components from the SLO header menu
and the observability alert details page as part of the [1Feedback
consolidation
initiative](elastic/kibana-team#2790). All
non-1Feedback widgets must be removed by the 9.5 release.

- Deletes `slo/.../feedback_button.tsx` and removes its import + usage
from `header_menu.tsx`

#### Before (SLOs)

<img width="1512" height="384" alt="Screenshot 2026-05-28 at 7 59 13 AM"
src="https://github.com/user-attachments/assets/d247350e-665b-4c1f-bf3f-576ddf8d35a9"
/>

#### After (SLOs)

<img width="1512" height="818" alt="Screenshot 2026-05-28 at 4 15 26 PM"
src="https://github.com/user-attachments/assets/77685981-eda9-4ced-99f3-6d92da1ba2e5"
/>

Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: jasonrhodes

x-pack/platform/plugins/private/translations/translations/de-DE.json

@@ -47448,7 +47448,6 @@
     "xpack.slo.errorRateChart.errorRateLabel": "Fehlerrate",
     "xpack.slo.eventsChartPanel.euiIcon.noResultsLabel": "keine Ergebnisse",
     "xpack.slo.extraInstanceIds.badge": "+{count, plural, one {# instance} other {# Instanzen}}",
-    "xpack.slo.featureFeedbackButtonLabel": "Feedback geben",
     "xpack.slo.featureRegistry.linkSloTitle": "SLOs",
     "xpack.slo.fieldSelector.all": "Alle",
     "xpack.slo.formattedConfigLabel.valid": "Es können nur gültige Formularkonfigurationen inspiziert werden.",

x-pack/platform/plugins/private/translations/translations/fr-FR.json

@@ -47288,7 +47288,6 @@
     "xpack.slo.errorRateChart.errorRateLabel": "Taux d'erreur",
     "xpack.slo.eventsChartPanel.euiIcon.noResultsLabel": "aucun résultat",
     "xpack.slo.extraInstanceIds.badge": "+{count, plural, one {# instance} other {# instances}}",
-    "xpack.slo.featureFeedbackButtonLabel": "Fournir des commentaires",
     "xpack.slo.featureRegistry.linkSloTitle": "SLO",
     "xpack.slo.fieldSelector.all": "Tous",
     "xpack.slo.formattedConfigLabel.valid": "Seules les configurations de formulaires valides peuvent être inspectées.",

x-pack/platform/plugins/private/translations/translations/ja-JP.json

@@ -47629,7 +47629,6 @@
     "xpack.slo.errorRateChart.errorRateLabel": "エラー率",
     "xpack.slo.eventsChartPanel.euiIcon.noResultsLabel": "結果なし",
     "xpack.slo.extraInstanceIds.badge": "+{count, plural, one {# instance} other {#件のインスタンス}}",
-    "xpack.slo.featureFeedbackButtonLabel": "フィードバックを送信",
     "xpack.slo.featureRegistry.linkSloTitle": "SLO",
     "xpack.slo.fieldSelector.all": "すべて",
     "xpack.slo.formattedConfigLabel.valid": "有効な形式の構成のみを検査できます。",

x-pack/platform/plugins/private/translations/translations/zh-CN.json

@@ -47619,7 +47619,6 @@
     "xpack.slo.errorRateChart.errorRateLabel": "错误率",
     "xpack.slo.eventsChartPanel.euiIcon.noResultsLabel": "无结果",
     "xpack.slo.extraInstanceIds.badge": "+{count, plural, one {# instance} other {# 个实例}}",
-    "xpack.slo.featureFeedbackButtonLabel": "反馈",
     "xpack.slo.featureRegistry.linkSloTitle": "SLO",
     "xpack.slo.fieldSelector.all": "全部",
     "xpack.slo.formattedConfigLabel.valid": "只能检查有效表单配置。",

x-pack/solutions/observability/plugins/slo/public/components/header_menu/header_menu.tsx

@@ -13,7 +13,6 @@ import { paths } from '@kbn/slo-shared-plugin/common/locators/paths';
 import { useKibana } from '../../hooks/use_kibana';
 import { usePluginContext } from '../../hooks/use_plugin_context';
 import { InspectorHeaderLink } from '../inspect/inspector_header_link';
-import { FeedbackButton } from '../../pages/slos/components/common/feedback_button';
 
 export function HeaderMenu(): React.ReactElement | null {
   const { http, theme, docLinks } = useKibana().services;
@@ -28,7 +27,6 @@ export function HeaderMenu(): React.ReactElement | null {
         <EuiFlexItem>
           <EuiHeaderLinks gutterSize="xs">
             <InspectorHeaderLink />
-            <FeedbackButton />
             <EuiHeaderLink
               color="primary"
               href={http.basePath.prepend('/app/observability/annotations')}