[ty] Do not promote literals in contravariant position (#21164)

## Summary

closes https://github.com/astral-sh/ty/issues/1463

## Test Plan

Regression tests

crates/ty_python_semantic/resources/mdtest/literal_promotion.md

@@ -0,0 +1,32 @@
+# Literal promotion
+
+There are certain places where we promote literals to their common supertype:
+
+```py
+reveal_type([1, 2, 3])  # revealed: list[Unknown | int]
+reveal_type({"a", "b", "c"})  # revealed: set[Unknown | str]
+```
+
+This promotion should not take place if the literal type appears in contravariant position:
+
+```py
+from typing import Callable, Literal
+
+def in_negated_position(non_zero_number: int):
+    if non_zero_number == 0:
+        raise ValueError()
+
+    reveal_type(non_zero_number)  # revealed: int & ~Literal[0]
+
+    reveal_type([non_zero_number])  # revealed: list[Unknown | (int & ~Literal[0])]
+
+def in_parameter_position(callback: Callable[[Literal[1]], None]):
+    reveal_type(callback)  # revealed: (Literal[1], /) -> None
+
+    reveal_type([callback])  # revealed: list[Unknown | ((Literal[1], /) -> None)]
+
+def double_negation(callback: Callable[[Callable[[Literal[1]], None]], None]):
+    reveal_type(callback)  # revealed: ((Literal[1], /) -> None, /) -> None
+
+    reveal_type([callback])  # revealed: list[Unknown | (((int, /) -> None, /) -> None)]
+```