`:` are not typed checked properly

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?

Type Checking

### Reproduction steps

```lua
---@param a number|string
function Foo.Bar(a)
return a:lower() -- Should warn as the code will error on a number input
end
```

### Additional Notes

https://github.com/LuaLS/lua-language-server/issues/2708#issuecomment-2337046169

### Log File

_No response_

Start by running the Lua reproduction in the issue with the Visual Studio Code extension and inspect the type-checking path for colon calls. Done means the analyzer warns that calling `lower` is unsafe when `a` may be a number.

Written by the indexing model from the issue text.