Bt warning fix

[Jad-ELHAJJ]

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Basic Info

Info	Please fill out this column
Ticket(s) this addresses	N/A
Primary OS tested on	Ubuntu
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

A fix PR making sure that BTCPP warning would never be logged. The final logic will be:

• If a user has conflicting IDs and specifies a file name, only the Behavior Tree (BT) from that file will be loaded. Other trees with the same ID will be ignored. Subtree functionality will fail if subtrees have conflicting IDs.
• If a user has unique IDs (no conflicts) and specifies a file name, all BTs are loaded, and the subtree feature works correctly.
• If a user has unique IDs and specifies a BT ID, all BTs are loaded, and the subtree feature works correctly.
• If a user has conflicting IDs and specifies a BT ID, an error is reported, but the system still attempts to load the BT corresponding to the specified ID.

Description of how this change was tested

• Tested all 4 conditions listed above on a behavior tree that includes subtrees.
• Tested with unit tests.

PS: codecov might complain about not covered code in bt_action_server_impl.hpp, but I added unit test for all 4 conditions. So the mock loadBehaviorTree in test_behavior_tree_node.cpp will be covering the new changes.

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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-*.

[codecov]

Codecov Report

❌ Patch coverage is 72.41379% with 8 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
...clude/nav2_behavior_tree/bt_action_server_impl.hpp	72.41%	8 Missing ⚠️

Files with missing lines	Coverage Δ
...clude/nav2_behavior_tree/bt_action_server_impl.hpp	88.54% <72.41%> (-1.86%)	⬇️

... and 9 files with indirect coverage changes

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[SteveMacenski]

Pull in main / rebase in order for CI to pass

[SteveMacenski]

LGTM now. Did you test this again that it works for the cases we had issue with before?

[SteveMacenski]

Indent error.