Darwin: Fix PlatformManagerHwTest XcvrLedFiles

[aalamsi22]

Summary

The PlatformManagerHwTest.XcvrLedFiles hw_test is currently failing because it expects the port led endpoints on Darwin to be "blue" and "amber". It is failing because:

1. Darwin doesn't support blue, but green instead. This is an edge case here and requires a special case.
2. The driver is outdated is refering to the color as "yellow".

This change addresses the first point by adding the edge case in the test for darwin. The second point is addressed by referencing the latest bsp version which renames yellow to amber.

Test

Running platform_manager_hw_test, the XcvrLedFiles test passes.

[==========] Running 8 tests from 1 test suite.
[----------] Global test environment set-up.
[----------] 8 tests from PlatformManagerHwTest
[ RUN      ] PlatformManagerHwTest.ExploreAsDeployed
[       OK ] PlatformManagerHwTest.ExploreAsDeployed (18413 ms)
[ RUN      ] PlatformManagerHwTest.ExploreAfterUninstallingKmods
[       OK ] PlatformManagerHwTest.ExploreAfterUninstallingKmods (20606 ms)
[ RUN      ] PlatformManagerHwTest.ExploreAfterUnloadingKmods
[       OK ] PlatformManagerHwTest.ExploreAfterUnloadingKmods (27896 ms)
[ RUN      ] PlatformManagerHwTest.PmExplorationStatusTransitions
[       OK ] PlatformManagerHwTest.PmExplorationStatusTransitions (18834 ms)
[ RUN      ] PlatformManagerHwTest.Symlinks
[       OK ] PlatformManagerHwTest.Symlinks (20401 ms)
[ RUN      ] PlatformManagerHwTest.XcvrCtrlFiles
[       OK ] PlatformManagerHwTest.XcvrCtrlFiles (19413 ms)
[ RUN      ] PlatformManagerHwTest.XcvrIoFiles
[       OK ] PlatformManagerHwTest.XcvrIoFiles (19889 ms)
[ RUN      ] PlatformManagerHwTest.XcvrLedFiles
[       OK ] PlatformManagerHwTest.XcvrLedFiles (19149 ms)
[----------] 8 tests from PlatformManagerHwTest (164605 ms total)

[----------] Global test environment tear-down
[==========] 8 tests from 1 test suite ran. (164605 ms total)
[  PASSED  ] 8 tests.