accounts/abi/bind: fixed unpacking error (#22230)

There was a dormant error with structured inputs that failed unpacking.
This commit fixes the error by switching casting to the better abi.ConvertType function.
It also adds a test for calling a view function that returns a struct

accounts/abi/bind/template.go

@@ -308,7 +308,7 @@ var (
 				return *outstruct, err
 			}
 			{{range $i, $t := .Normalized.Outputs}} 
-			outstruct.{{.Name}} = out[{{$i}}].({{bindtype .Type $structs}}){{end}}
+			outstruct.{{.Name}} = *abi.ConvertType(out[{{$i}}], new({{bindtype .Type $structs}})).(*{{bindtype .Type $structs}}){{end}}
 
 			return *outstruct, err
 			{{else}}