When using string literals in equality operators, should the size affect whether the equality is successful?
I am testing with the below ksy definitions and the attached text file.

```ksy
meta:
  id: try
  
seq:
  - id: thing
    type: str
    encoding: UTF-16LE
    size: 20
    
instances:
  is_last_parti:
    value:
      thing == "last_parti"
```

[last_parti.txt](https://github.com/kaitai-io/kaitai_struct/files/7220351/last_parti.txt)

When size is set to 20, the value instance is true.
If the size is set to 22 or higher, the value instance is false even though the string does not continue past 20.

Also when size=22, making the string into "last_parti\0\0" makes it false, but making it "last_parti\0" is true even though I only specified 1 byte from octal? It's true when I do "last_parti\u0000", as expected. But for longer strings its a PITA to keep appending \u0000 at the end.
UTF-16 doesn't work with terminators otherwise I'd use that.

If the string does not use the whole buffer defined for it should string comparison with a literal fail?