Fix "mistral/mistral-medium-latest" entry in "model_prices_and_context_window.json"

[clemparpa]

litellm/model_prices_and_context_window.json

Lines 3552 to 3562 in 652b569

	"mistral/mistral-medium-latest": {
	"max_tokens": 8191,
	"max_input_tokens": 32000,
	"max_output_tokens": 8191,
	"input_cost_per_token": 0.0000027,
	"output_cost_per_token": 0.0000081,
	"litellm_provider": "mistral",
	"mode": "chat",
	"supports_assistant_prefill": true,
	"supports_tool_choice": true
	},

We also need to update model_prices_and_context_window_backup.json.

Mistral just released a new model for mistral-medium-latest. costs are 0.4/M input and 2/M output

[regismesquita]

I have created a PR for it, currently in review. #10729