Add ispathvalid maxcost

[mini-1235]

---

Basic Info

Info	Please fill out this column
Ticket(s) this addresses	#4756
Primary OS tested on	Ubuntu 24.04
Robotic platform tested on	Custom simulation environment
Does this PR contain AI generated software?	No

---

Description of contribution in a few bullet points

• Add max cost as described in the issue
• Add corresponding test

Description of documentation updates required from your changes

Add new parameter description https://docs.nav2.org/configuration/packages/bt-plugins/conditions/IsPathValid.html

Description of how this change was tested

Wrote a new test to test this and also tested on custom simulation env

---

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