fix: resolve uncloseable database restore modal on MariaDB import (#7335)

Fixes the "Snapshot missing on Livewire component" error that occurs when
toggling the "Backup includes all databases" checkbox during MariaDB database
import operations.

Root Cause:
- ActivityMonitor component was initialized without proper lifecycle hooks
- When parent Import component re-rendered (via checkbox toggle), the
  ActivityMonitor's Livewire snapshot became stale
- Missing null checks caused errors when querying with undefined activityId
- No state cleanup when slide-over closed, causing issues on subsequent opens

Changes:
- Add updatedActivityId() lifecycle hook to ActivityMonitor for proper hydration
- Add defensive null check in hydrateActivity() to prevent query errors
- Track activityId in Import component for state management
- Add slideOverClosed event dispatch in slide-over component
- Add event listener in Import component to reset activityId on close

Testing:
- Manually verify checkbox toggle doesn't trigger popup
- Verify actual restore operations work correctly
- Test both file-based and S3-based restore methods
- Ensure X button properly closes the modal
- Verify no console errors or Livewire warnings

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

resources/views/components/slide-over.blade.php

@@ -1,7 +1,13 @@
 @props(['closeWithX' => false, 'fullScreen' => false])
 <div x-data="{
     slideOverOpen: false
-}" {{ $attributes->merge(['class' => 'relative w-auto h-auto']) }}>
+}"
+x-init="$watch('slideOverOpen', value => {
+    if (!value) {
+        $dispatch('slideOverClosed')
+    }
+})"
+{{ $attributes->merge(['class' => 'relative w-auto h-auto']) }}>
     {{ $slot }}
     <template x-teleport="body">
         <div x-show="slideOverOpen" @if (!$closeWithX) @keydown.window.escape="slideOverOpen=false" @endif