Bugfix inactive publishers (backport #5748)

[mergify]

Basic Info

Info	Please fill out this column
Ticket(s) this addresses	#5710
Primary OS tested on	Ubuntu 24.04 docker container
Robotic platform tested on	Gazebo simulation of a USV
Does this PR contain AI generated software?	No
Was this PR description generated by AI software?	No

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Description of contribution in a few bullet points

Prevent the costmap_2d_publisher from trying to publish when it is not active.

Description of documentation updates required from your changes

N/A

Description of how this change was tested

Replicated the steps to produce the issue in #5710 and did not see the issue.

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Future work that may be required in bullet points

This is not likely the root cause for the out-of-bounds index access but:

• it seems logically correct to prevent publication unless active
• it has the affect of side-stepping the issue

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
• Should this be backported to current distributions? If so, tag with backport-*.

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This is an automatic backport of pull request #5748 done by [Mergify](https://mergify.com).

[mergify]

@mergify[bot], all pull requests must be targeted towards the main development branch.
Once merged into main, it is possible to backport to @kilted, but it must be in main
to have these changes reflected into new distributions.