Extracting email functions into a service (#14802)

* Extracting email functions into a service

* Fixing two shadowing errors

* Address PR review comments

Co-authored-by: Mattermod <mattermod@users.noreply.github.com>

app/team.go

@@ -1148,7 +1148,7 @@ func (a *App) InviteNewUsersToTeamGracefully(emailList []string, teamId, senderI
 
 	if len(goodEmails) > 0 {
 		nameFormat := *a.Config().TeamSettings.TeammateNameDisplay
-		a.SendInviteEmails(team, user.GetDisplayName(nameFormat), user.Id, goodEmails, a.GetSiteURL())
+		a.Srv().EmailService.SendInviteEmails(team, user.GetDisplayName(nameFormat), user.Id, goodEmails, a.GetSiteURL())
 	}
 
 	return inviteListWithErrors, nil
@@ -1231,7 +1231,11 @@ func (a *App) InviteGuestsToChannelsGracefully(teamId string, guestsInvite *mode
 
 	if len(goodEmails) > 0 {
 		nameFormat := *a.Config().TeamSettings.TeammateNameDisplay
-		a.sendGuestInviteEmails(team, channels, user.GetDisplayName(nameFormat), user.Id, goodEmails, a.GetSiteURL(), guestsInvite.Message)
+		senderProfileImage, _, err := a.GetProfileImage(user)
+		if err != nil {
+			a.Log().Warn("Unable to get the sender user profile image.", mlog.String("user_id", user.Id), mlog.String("team_id", team.Id), mlog.Err(err))
+		}
+		a.Srv().EmailService.sendGuestInviteEmails(team, channels, user.GetDisplayName(nameFormat), user.Id, senderProfileImage, goodEmails, a.GetSiteURL(), guestsInvite.Message)
 	}
 
 	return inviteListWithErrors, nil
@@ -1268,7 +1272,7 @@ func (a *App) InviteNewUsersToTeam(emailList []string, teamId, senderId string)
 	}
 
 	nameFormat := *a.Config().TeamSettings.TeammateNameDisplay
-	a.SendInviteEmails(team, user.GetDisplayName(nameFormat), user.Id, emailList, a.GetSiteURL())
+	a.Srv().EmailService.SendInviteEmails(team, user.GetDisplayName(nameFormat), user.Id, emailList, a.GetSiteURL())
 
 	return nil
 }
@@ -1292,12 +1296,15 @@ func (a *App) InviteGuestsToChannels(teamId string, guestsInvite *model.GuestsIn
 
 	if len(invalidEmailList) > 0 {
 		s := strings.Join(invalidEmailList, ", ")
-		err := model.NewAppError("InviteGuestsToChannels", "api.team.invite_members.invalid_email.app_error", map[string]interface{}{"Addresses": s}, "", http.StatusBadRequest)
-		return err
+		return model.NewAppError("InviteGuestsToChannels", "api.team.invite_members.invalid_email.app_error", map[string]interface{}{"Addresses": s}, "", http.StatusBadRequest)
 	}
 
 	nameFormat := *a.Config().TeamSettings.TeammateNameDisplay
-	a.sendGuestInviteEmails(team, channels, user.GetDisplayName(nameFormat), user.Id, guestsInvite.Emails, a.GetSiteURL(), guestsInvite.Message)
+	senderProfileImage, _, err := a.GetProfileImage(user)
+	if err != nil {
+		a.Log().Warn("Unable to get the sender user profile image.", mlog.String("user_id", user.Id), mlog.String("team_id", team.Id), mlog.Err(err))
+	}
+	a.Srv().EmailService.sendGuestInviteEmails(team, channels, user.GetDisplayName(nameFormat), user.Id, senderProfileImage, guestsInvite.Emails, a.GetSiteURL(), guestsInvite.Message)
 
 	return nil
 }