Speed up unit test and skip unstable test

[superstar54]

In the previous unit test, one needed to sleep for a time manually to wait for a task state. The sleep time needs to be chosen carefully to make sure the state is reached. This PR allows the WorkGraph to wait for the particular states of a task.

# wait add1 to be finished.
wg.wait(tasks={"add1": ["FINISHED"]}, timeout=20)
# wait for the workgraph to launch add1
wg.wait(tasks={"add1": ["CREATED", "WAITING", "RUNNING", "FINISHED"]}, timeout=20)

This speeds up the test and makes the test more robust.

To speed up the test, I also

• Remove unused task, duplicated test.
• Replace the calcjob task with the calcfunction task.

Skip unstable test

I skipped the test for playing the paused task; it seems the daemon is not responding to the play signal. This should be a problem of AiiDA test fixtures.

Time for the pytest

python version	AiiDA version	Time (This PR)	Time (Previous)
3.9	2.6	13 s	17 s
3.11	2.6	11 s	14 s
3.12	2.6	17 s	23 s

TODO: find why Python 3.12 is slow.

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 98.36066% with 1 line in your changes missing coverage. Please review.

Project coverage is 75.96%. Comparing base (5937b88) to head (6423864).
Report is 7 commits behind head on main.

Files	Patch %	Lines
aiida_workgraph/workgraph.py	93.33%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #205      +/-   ##
==========================================
+ Coverage   75.75%   75.96%   +0.20%     
==========================================
  Files          70       70              
  Lines        4615     4709      +94     
==========================================
+ Hits         3496     3577      +81     
- Misses       1119     1132      +13     

Flag	Coverage Δ
python-3.11	75.96% <98.36%> (+0.29%)	⬆️
python-3.9	?

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