Added quickstart_test.py files for each Python sample, which compile and
run the agent as a standalone application to validate its end-to-end
functionality.
The test condition ensures the sample runs to completion and produces an
output which confirms the agent is not breaking. Additionally, i
introduced a secondary check for essential keywords from a golden.txt
file, logging their presence without failing the test.
Running test file:
execute this cmd from terminal
```
ORCH_NAME=adk pytest
```
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