Fix linkage to a same global target of different package components in CMake generators

[danimtb]

Changelog: BugFix: Fix linkage to a same global target of different package components in cmake_find_package/_multi generators.
Docs: conan-io/docs#1946

• Refer to the issue that supports this Pull Request: closes [bug] CMake find_package generator creates conflicts when multiple deps have the same export namespace #7889
• If the issue has missing info, explain the purpose/use case/pain/need that covers this Pull Request.
• I've read the Contributing guide.
• I've followed the PEP8 style guides for Python code.
• I've opened another PR in the Conan docs repo to the develop branch, documenting this one.

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[memsharded]

It is looking good, maybe improving the tests to make sure that the APPEND work, and nonstd::nonstd is now the accumulated of all.

[jgsogo]

btw, I would modify the changelog, IMO this is more like a feature.

(I'm not merging because develop is 🔴 for several builds now and I don't want to add more noise if something is really broken)