fix: Home > Project Settings > Integrations- Integrations category la…

…bels do not inform user of related results (elastic#190235)

Closes:
elastic/observability-accessibility#136

### Description

`Home` > `Project Settings` > `Integrations`- Integrations category
labels do not inform user of related results.

### Steps to recreate

Pre-requisite:
Screen reader is activated

1. Navigate to the `Serverless Observability Solution `instance.
2. Click `Project Settings` in lower Left Nav
3. Select `Integrations`
4. Keyboard navigate to the Browse Integrations list
5. Tab through the list

### What was changed:?

1. The `aria-label` attribute has been set for the associated
`EuiFacetButton` component

### Screen: 

#### a11y tree:
<img width="990" alt="image"
src="https://github.com/user-attachments/assets/4c83314e-a980-4a44-9191-b070ffa621ed">

#### DOM:
<img width="990" alt="image"
src="https://github.com/user-attachments/assets/8a4c02cd-9688-499e-982f-a6a22c91d62c">

x-pack/plugins/fleet/public/applications/integrations/sections/epm/screens/home/category_facets.tsx

@@ -89,6 +89,14 @@ export function CategoryFacets({
               id={category.id}
               quantity={category.count}
               onClick={() => onCategoryChange(category)}
+              aria-label={i18n.translate('xpack.fleet.epmList.facetButton.ariaLabel', {
+                defaultMessage:
+                  '{key}, {count} {count, plural, one { integration } other { integrations }}',
+                values: {
+                  key: category.title,
+                  count: category.count,
+                },
+              })}
             >
               {category.title}
             </EuiFacetButton>