ci: fix with_coverage, isolate not unstable but extra_functional

[s8sato]

Description

1. redefine with_coverage step to exclude client integration tests
   • and to include p2p integration tests
2. expand the exception of the client integration tests from unstable_network to extra_functional

Linked issue

1. closes Fix with_coverage #4488 (comment)
   • opens coverage measurement targets #4584
2. sometimes integration step fails due to some flaky extra_functional tests

Benefits

2. isolation of flaky tests more in line with current realities

Checklist

• I've read CONTRIBUTING.md
• I've used the standard signed-off commit format (or will squash just before merging)
• All applicable CI checks pass (or I promised to make them pass later)
• (optional) I've written unit tests for the code changes
• I replied to all comments after code review, marking all implemented changes with thumbs up