Few frontend optimizations

[odeimaiz]

What do these changes do?

• Throttle study update
• Stop asking for node's state when study gets closed
• Do not ask for checkpoints if disabled (related to ✨ Enable/disable plugins marked as "under development" via env vars #2824)
• Wait for successful :open study, before rendering nodes (fixes missing connection arrows in WB osparc-issues#592)

Related issue/s

closes ITISFoundation/osparc-issues#592

How to test

Checklist

[codecov]

Codecov Report

Merging #2823 (129da75) into master (fcc70d3) will decrease coverage by 0.0%.
The diff coverage is n/a.

@@           Coverage Diff            @@
##           master   #2823     +/-   ##
========================================
- Coverage    78.9%   78.8%   -0.1%     
========================================
  Files         671     671             
  Lines       27290   27290             
  Branches     3148    3148             
========================================
- Hits        21532   21527      -5     
- Misses       4997    5000      +3     
- Partials      761     763      +2     

Flag	Coverage Δ
integrationtests	65.8% <ø> (-0.1%)	⬇️
unittests	74.4% <ø> (-0.1%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
...rvice-library/src/servicelib/common_aiopg_utils.py	88.2% <0.0%> (-8.9%)	⬇️
...rvice_datcore_adapter/utils/requests_decorators.py	71.0% <0.0%> (-7.9%)	⬇️
...tor_v2/modules/dynamic_sidecar/scheduler/events.py	94.7% <0.0%> (-1.2%)	⬇️
...ector_v2/modules/dynamic_sidecar/scheduler/task.py	85.9% <0.0%> (-0.6%)	⬇️
...webserver/computation_comp_tasks_listening_task.py	78.6% <0.0%> (+0.9%)	⬆️
...car/src/simcore_service_dask_sidecar/dask_utils.py	90.7% <0.0%> (+1.0%)	⬆️
.../src/simcore_service_webserver/director_v2_core.py	67.9% <0.0%> (+1.0%)	⬆️

[KZzizzle]

thanks for fixing osparc!