validate email

[todo]

NotificationService/controllers/mail.js

Lines 7 to 12 in 92a6819

	// TODO: validate email
	if (!receiver) return;
	if (!templateId) return;
	mailjet
	.post('send', {

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This issue was generated by todo based on a TODO comment in 92a6819. It's been assigned to @GPlay97 because they committed the code.