[Behaviours/BTMan] Implemented unit testing for PathTo signal

Summary

Implemented testing for PathTo signal in BehaviourTreeManager. Uses QSignalSpy to observe signal and read the arguments passed into signal. The unit test uses a GSR tree that only contains the NavigateTo subtree, as this is the only subtree that uses the node RequestAndWaitForNewPath.

Testing

• Created tests
• Updated tests
• Tested in simulation (integration tests)
• Tested in real robot (if applicable)
• No tests (reason):

test using BoostUT unit_test executable

Changes

• Added Qt:Test component into Cmake

Blast Radius

anything that is affected by addition of Qt Test component

Checklist

• All relevant unit tests are passing
• Documentation updated (if applicable)
• No debug logs or commented-out code

Closes #612 (closed)