Fix collision monitor test suite for humble

[jncfa]

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Basic Info

Info	Please fill out this column
Ticket(s) this addresses	#5230
Primary OS tested on	(Ubuntu)
Robotic platform tested on
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

• Removes usages of the collision monitor state as this is not published in humble, only in Iron+;

Description of documentation updates required from your changes

Description of how this change was tested

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Future work that may be required in bullet points

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-*.

[mergify]

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

[SteveMacenski]

Unfortunately, this cannot be backported to Humble due to breaking ABI / API that existing users are relying on for their own work