[CostmapTopicCollisionChecker] Alternative constructor with footprint string

[doisyg]

---

Basic Info

Info	Please fill out this column
Ticket(s) this addresses
Primary OS tested on	Ubuntu
Robotic platform tested on	Dexory Robot
Does this PR contain AI generated software?

---

Description of contribution in a few bullet points

I needed to use the CostmapTopicCollisionChecker but with a custom footprint, NOT one served from a topic with FootprintSubscriber. So I added a constructor building a footpring from a string (same format as everywhere else).

Description of documentation updates required from your changes

Don't see any.

Description of how this change was tested

Dexory robot for a few days.

---

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

[SteveMacenski]

All the system tests failed, so rerunning CI to see if that fixes it

[SteveMacenski]

Otherwise, just waiting to make sure CI passes that it wasn't just a fluke (but now I"m actually wondering if all the CI tests failed due to this issue I mention below)

[codecov]

Codecov Report

Attention: Patch coverage is 22.22222% with 7 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
...costmap_2d/src/costmap_topic_collision_checker.cpp	22.22%	7 Missing ⚠️

Files with missing lines	Coverage Δ
...av2_costmap_2d/costmap_topic_collision_checker.hpp	100.00% <ø> (ø)
...costmap_2d/src/costmap_topic_collision_checker.cpp	76.31% <22.22%> (-17.24%)	⬇️

... and 6 files with indirect coverage changes

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[SteveMacenski]

LGTM - just need to error check and provided a more concise version of the sub check

[doisyg]

Tested at Dexory with the latest changes. Happy now.