Use uv run for capabilities as well

Author: ishymko

.github/workflows/run-tck.yaml

@@ -99,7 +99,7 @@ jobs:
         id: run-tck-capabilities
         timeout-minutes: 5
         run: |
-          ./run_tck.py --sut-url ${{ env.SUT_JSONRPC_URL }} --category capabilities --transports jsonrpc
+          uv run run_tck.py --sut-url ${{ env.SUT_JSONRPC_URL }} --category capabilities --transports jsonrpc
         working-directory: tck/a2a-tck
 
       - name: Stop SUT