cmComputeLinkInformation: Track targets named by TARGET_OBJECTS sources

Since !8197 (merged), the return value of cmCommonTargetGenerator::GetLinkedTargetDirectories must account for linked object libraries because they may provide modules (see #25112 (closed)). These were added by !8645 (merged). However, targets named by $<TARGET_OBJECTS:...> sources are also needed (see #25365 (closed)).

The latter were added by commit !8923 (merged). However, its approach added link entries not actually specified by projects. It also incorrectly re-used cmComputeLinkDepends::AddLinkObject for object library targets when it is meant for their individual object files. These problems caused additional regressions (see #25417 (closed)). Revert the implementation parts of those commits and leave behind an assertion and comment to help avoid the mistake in the future. Instead, track targets named by $<TARGET_OBJECTS:...> sources with a dedicated member.

Issue: #25112 (closed)
Issue: #25365 (closed)
Fixes: #25417 (closed)
Co-authored-by: @ben.boeckel
Manual-backport: release-3.27
Backport: release