Fix isCurrent in obstacle layer and assure CostmapTopicCollisionChecker only uses current costmaps

[schupf2]

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Basic Info

Info	Please fill out this column
Ticket(s) this addresses	#4734
Primary OS tested on	Ubuntu
Robotic platform tested on	--
Does this PR contain AI generated software?	No

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Description of contribution in a few bullet points

• The costmap is only published if it's current, such that the CostmapTopicCollisionChecker can be relied on again.
• Fix problems in the obstacle layer, causing it to return true on isCurrent(), after a reset (even if no data was received).
• For a detailed argumentation, please have a look at the communications in ClearEntireCostmap returns before all costmap layer include valid data #4734

Description of documentation updates required from your changes

• I didn't add documentation so far, but am open to suggestions. Maybe the change regarding the costmap publishing could be added.

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Future work that may be required in bullet points

• The same changes that were made to the obstacle layer are also required for the STVL. I will open a related pull request once this one was merged.

For Maintainers:

• Check that any new parameters added are updated in docs.nav2.org
• Check that any significant change is added to the migration guide
• Check that any new features OR changes to existing behaviors are reflected in the tuning guide
• Check that any new functions have Doxygen added
• Check that any new features have test coverage
• Check that any new plugins is added to the plugins page
• If BT Node, Additionally: add to BT's XML index of nodes for groot, BT package's readme table, and BT library lists

[mergify]

@schupf2, your PR has failed to build. Please check CI outputs and resolve issues.
You may need to rebase or pull in main due to API changes (or your contribution genuinely fails).

[schupf2]

@schupf2, your PR has failed to build. Please check CI outputs and resolve issues. You may need to rebase or pull in main due to API changes (or your contribution genuinely fails).

Thank you - I just saw it as well :).
I probably already fixed the problem, but meanwhile I'll change this PR to Draft.