fix: resolve type errors in lambda parameter inference

- Add explicit type annotation for exp_t parameter
- Remove incorrect GenericType.t access in context.lua
- Ensure proper type checking for FunctionType parameters

Fixes compilation errors in context.tl:2387 and visitors.tl:1720

Author: Nikita-baghela07

teal/check/context.lua

@@ -2378,14 +2378,9 @@ function Context:infer_lambda_parameters(node, expected)
       return
    end
 
-   -- normalize expected type (CRITICAL)
    expected = self:to_structural(expected)
 
-   if expected.typename == "generic" then
-      expected = expected.t
-   end
-
-   if expected.typename ~= "function" then
+   if not (expected.typename == "function") then
       return
    end
 

teal/check/context.tl

@@ -2383,7 +2383,7 @@ function Context:infer_lambda_parameters(node: Node, expected: FunctionType)
    -- Infer parameter types only if arity matches
    if #actual_params == #expected_params then
       for i, param in ipairs(actual_params) do
-         local exp_t = expected_params[i]
+         local exp_t: Type = expected_params[i]
 
          if not param.argtype then
             -- infer for unannotated parameters only