test: add regression for chatbot

[bwanglzu]

Given a system under test, test_chatbot depends on the index flow to be fired. While f.block blocked the process. I did some search and find the official plugin: pytest-xprocess

pytest plugin for managing processes across test runs.

This plugin:

1. Bootstrap hello_world example in another process.
2. Monitor system logs to check if it is ready to test using pattern matching.
3. Run the test.
4. Kill the process.

This PR completes regression tests for three examples.

[codecov]

Codecov Report

Merging #2218 (0de3afa) into master (5c5cfef) will decrease coverage by 0.08%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master    #2218      +/-   ##
==========================================
- Coverage   89.12%   89.03%   -0.09%     
==========================================
  Files         208      208              
  Lines       11226    11226              
==========================================
- Hits        10005     9995      -10     
- Misses       1221     1231      +10     

Flag	Coverage Δ
daemon	50.26% <100.00%> (ø)
jina	89.38% <100.00%> (-0.10%)	⬇️

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Impacted Files	Coverage Δ
jina/__init__.py	73.49% <100.00%> (ø)
jina/clients/base.py	78.51% <0.00%> (-2.48%)	⬇️
jina/peapods/zmq/__init__.py	80.80% <0.00%> (-2.17%)	⬇️
jina/peapods/runtimes/zmq/zed.py	87.94% <0.00%> (-1.42%)	⬇️
jina/peapods/peas/__init__.py	93.69% <0.00%> (+1.80%)	⬆️

---

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[github-actions]

Latency summary

Current PR yields:

• 😶 index QPS at 1000, delta to last 3 avg.: +0%
• 😶 query QPS at 14, delta to last 3 avg.: -5%

Breakdown

Version	Index QPS	Query QPS
current	1000	14
1.0.13	994	14
1.0.12	1011	15

Backed by latency-tracking. Further commits will update this comment.

[bwanglzu]

please DO NOT MERGE before CI fixed.

[nan-wang]

LGTM👍