Feature Request: Support array table diagnose when a constant variable as key in lua 5.4

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

It would be nice if when trying to use a constant variable as key of array the hint is also right. Thanks

`local ONE_INDEX = 1

---@class Test
---@field [1] math
local _M = {
math
}

-- hint the math
_M[ONE_INDEX].floor(1.1)`

### Actual Behaviour

can't recognize the object

### Reproduction steps

Empty

### Additional Notes

_No response_

### Log File

_No response_

Start by reproducing the Lua 5.4 example in the VS Code extension and trace the diagnostic or type-inference path for indexing with a variable. Done means the language server recognizes _M[ONE_INDEX] as the annotated array entry and provides the expected hint without unrelated regressions.

Written by the indexing model from the issue text.