Update zephyr unit tests workflow filters

Removed iris dependency from zephyr unit test filters.

Author: rjpower

.github/workflows/zephyr-unit-tests.yaml

@@ -25,8 +25,6 @@ jobs:
           filters: |
             relevant:
               - 'lib/zephyr/**'
-              # zephyr depends on iris and fray; run zephyr tests on any upstream change.
-              - 'lib/iris/**'
               - 'lib/fray/**'
               - 'uv.lock'
               - '.github/workflows/zephyr-unit-tests.yaml'