`CollectEndorsementsView` might not release all resources

[ale-linux]

The CollectEndorsementsView view contains the following code

func (c *CollectEndorsementsView) Call(context view.Context) (interface{}, error) {
	metrics := GetMetrics(context)

	externalWallets := make(map[string]ExternalWalletSigner)
	// 1. First collect signatures on the token request
	issueSigmas, err := c.requestSignaturesOnIssues(context, externalWallets)
	if err != nil {
		return nil, errors.WithMessagef(err, "failed requesting signatures on issues")
	}

	transferSigmas, err := c.requestSignaturesOnTransfers(context, externalWallets)
	if err != nil {
		return nil, errors.WithMessagef(err, "failed requesting signatures on transfers")
	}

	// signal the external wallets that the process is completed
	logger.DebugfContext(context.Context(), "Inform external wallets that endorsement is complete")
	for id, signer := range externalWallets {
		if err := signer.Done(); err != nil {
			logger.ErrorfContext(context.Context(), "failed to signal done external wallet [%s]", id)
			logger.Errorf("failed to signal done external wallet [%s]", id)
		}
	}

It is possible that Done is not called on all external wallets in case some error occurs.