PLT-6217 Fixes system message posted to Town Square when a member leaves a team (#7752)

* Fixes system message posted to Town Square when adding/removing team member (#6483)

Fixes unit test method call to match RemoveUserFromTeam modification (#6483)

Fixes system message posted to Town Square when adding/removing team member (#6483)

Removes unnessary error message

* Updates system message when a user leaves a team (#6483)

* Changes system message when a user is removed from team (#6483)

* Adds a new string to be post to town-square when a member is added to a team (#6483)

api/team.go

@@ -179,7 +179,7 @@ func removeUserFromTeam(c *Context, w http.ResponseWriter, r *http.Request) {
 		}
 	}
 
-	if err := c.App.RemoveUserFromTeam(c.TeamId, userId); err != nil {
+	if err := c.App.RemoveUserFromTeam(c.TeamId, userId, c.Session.UserId); err != nil {
 		c.Err = err
 		return
 	}