Incorrect type on string-key fields when combined with `[string]`

まだ誰も着手していません。

### 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?

Type Checking

### Expected Behaviour

we have a (generated) class like
```
---@class GlobalModSettings
---@field ["heat-visualizer-updates-per-surface-per-tick"] ModSetting
---@field ["nixie-tube-update-speed-alpha"] ModSetting
---@field ["nixie-tube-update-speed-numeric"] ModSetting
---@field [string] ModSetting<(int32)|(double)|(boolean)|(string)|(Color)>
```

which has narrower types for the known entries and a general type for the "everything else" field, but when i then use this type like
```
local x = settings.global["heat-visualizer-updates-per-surface-per-tick"]
```
`x` is given the type from the `[string]` field, rather than the one that is an exact match for that specific string

### Actual Behaviour

(this template is always off screen and i've written the whole thing in the first box...)

### Reproduction steps

(this template is always off screen and i've written the whole thing in the first box...)

### Additional Notes

_No response_

### Log File

_No response_

リポジトリのファイルもテストも指定されていません。まず Visual Studio Code extension を通じて Lua language server の注釈付き GlobalModSettings ルックアップを再現し、次にインデックス付きフィールドの型解決を追跡してください。完了条件は、完全一致する文字列キーのフィールドが、より広い [string] フィールド型ではなく、より狭い型を受け取ることです。

索引モデルが issue の本文から書いたものです。