fix: lower-case Graph errors (staticcheck)

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

internal/provider/azure/account.go

@@ -204,11 +204,11 @@ func (p *Provider) Groups(ctx context.Context) ([]string, error) {
 		resp.Body.Close()
 		switch {
 		case err != nil:
-			return nil, fmt.Errorf("Microsoft Graph: %w", err)
+			return nil, fmt.Errorf("listing groups from Microsoft Graph: %w", err)
 		case page.Error != nil:
-			return nil, fmt.Errorf("Microsoft Graph: %s", page.Error.Message)
+			return nil, fmt.Errorf("listing groups from Microsoft Graph: %s", page.Error.Message)
 		case resp.StatusCode != http.StatusOK:
-			return nil, fmt.Errorf("Microsoft Graph: %s", resp.Status)
+			return nil, fmt.Errorf("listing groups from Microsoft Graph: %s", resp.Status)
 		}
 		for _, v := range page.Value {
 			if v.Type == "#microsoft.graph.group" && v.Name != "" {