utils/deps: always show missing deps

[doronbehar]

When trying to use PaddleX on NixOS, which doesn't allow imperative installation of Python packages with pip, I found this change to be useful, and thought that other users might benefit from it. Original commit message:

When first trying out paddlex, it can be hard to figure out how to increase the logging verbosity. If there are missing dependencies and this raises an error, seeing the exact list is helpful either way.

[paddle-bot]

Thanks for your contribution!

[CLAassistant]

All committers have signed the CLA.

[Bobholamovic]

Please merge the commits to the develop branch.

[doronbehar]

Please merge the commits to the develop branch.

Done.

[Bobholamovic]

Considering that is_extra_available is sometimes used only to check whether the extra is available in order to branch the logic, logging an error-level message here does not seem appropriate.

I suggest adding a parameter to is_extra_available to control whether an error-level log should be emitted. This flag can then be enabled in assertion-style functions such as require_extra, so that users can still receive helpful diagnostic information when necessary.

[doronbehar]

OK I see this makes sense, I wasn't aware that is_extra_available was used in a way that shouldn't raise an error somewhere. I modified it and modified only require_extra to make it log an error in case a dependency is missing.