fix(datasource/gitlab-packages): prefer checking for conan_package_name if it exists

[FFace32]

Changes

Checks if conan_package_name exists and matches the filtered package name for the gitlab-packages datasource.

Context

When querying for uploaded Conan packages on GitLab, the name value contains the version and the channel as well, and this doesn't pass the filter in lib/modules/datasource/gitlab-packages/index.ts.

conan_package_name, if it exists, contains only the package name.

This can also be seen in the GitLab documentation as an example here: https://gitlab.com/gitlab-org/gitlab/-/blob/master/doc/api/packages.md?plain=1#L69-70

Documentation (please check one with an [x])

• I have updated the documentation, or
• No documentation update is required

How I've tested my work (please select one)

I have verified these changes via:

• Code inspection only, or
• Newly added/modified unit tests, or
• No unit tests but ran on a real repository, or
• Both unit tests + ran on a real repository

[rarkins]

Please add a test

[FFace32]

Should I update the index.spec.ts.snap snapshot?

It seems like that's the reason the pipeline fails.