Make conan_data visible to pylint

[uilianries]

Since Conan 1.16.0 we are able to add a data file called conandata.yml, which can be retrieved by self.conan_data in our recipe. However, that member is lazy and Conan's linter detects it as non-member before exporting.

Changelog: Fix: Make conan_data visible to pylint (#5327)
Docs: Omit

fixes #5327

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