false positive in undefined-field

Nobody has claimed this yet.

### How are you using the lua-language-server?

Visual Studio Code Extension (sumneko.lua)

### Which OS are you using?

Windows

### What is the issue affecting?

Diagnostics/Syntax Checking

### Expected Behaviour

```lua
function F()
G = 1
end

function F2()
G = { a = 1 }
end

F()
F2()

print(G.a)

```

expected no error

### Actual Behaviour

but got an error

### Reproduction steps

enable vscode extension

### Additional Notes

_No response_

### Log File

_No response_

Start by reproducing the snippet in the Visual Studio Code extension on Windows with diagnostics and syntax checking enabled. Trace the undefined-field diagnostic for the global G across F and F2, then verify that the example no longer reports an error after the behavior is corrected.

Written by the indexing model from the issue text.