Change the way of enable/disable litellm logging

[chenmoneygithub]

We introduced litellm logging suppression in #1768, but we were configuring litellm inside the __init__ call. So if users do:

lm = dspy.LM("...")
dspy.settings.configure(suppress_debug_info=False)
lm("some query")

Then the logging won't be turned on. In this PR I am introducing a pair of util functions: dspy.clients.enable_litellm_logging() and dspy.client.disable_litellm_logging() to turn on/off the litellm logging dynamically.

[okhat]

Thank you, @chenmoneygithub! I like this! But should it just be dspy.configure(litellm_logging=True/False)?

If you think the answer is no, feel free to merge this!

[chenmoneygithub]

@okhat Thanks! I took a second look at dspy.settings.configure(), and seems right now it's just updating the global state dict instead of running any dynamic configuration:

    def configure(self, inherit_config: bool = True, **kwargs):
        """Set configuration settings.

        Args:
            inherit_config (bool, optional): Set configurations for the given, and use existing configurations for the rest. Defaults to True.
        """
        if inherit_config:
            config = {**self.config, **kwargs}
        else:
            config = {**kwargs}

        self.__append(config)

So for now I feel it's better not change this pattern. But in the future (after we deprecate the dsp directory) we may want to have a centralized namespace like dspy.settings that is a collection of dynamic configs, e.g., dspy.settings.disable_litellm_logging() and dspy.settings.enable_verbose_logging().