PID in Blocks not able to accept symbolic parameters

The following code gives `ERROR: TypeError: non-boolean (Num) used in boolean context`

```julia
using ModelingToolkit
using ModelingToolkitStandardLibrary.Blocks

@parameters k = 3 Ti = 0.5 Td = 1 / 100
@named pid_controller = PID(;k, Ti, Td)
```