fix: Add waiting time for chart animation when screenshot

[u-aiaa]

SUMMARY

Since the chart in the report screenshot is sent before the end of the animation
Added a wait time for chart animation when screenshot.

New configuration keys:
SCREENSHOT_SELENIUM_ANIMATION_WAIT: in seconds

ADDITIONAL INFORMATION

• Has associated issue:
• Changes UI
• Includes DB Migration (follow approval process in SIP-59)
  • Migration is atomic, supports rollback & is backwards-compatible
  • Confirm DB migration upgrade and downgrade tested
  • Runtime estimates and downtime expectations provided
• Introduces new feature or API
• Removes existing feature or API

[junlincc]

Thank you so much for your contribution! we will review your proposed solution and code soon

[junlincc]

change make sense. explained in the original issue.

[codecov]

Codecov Report

Merging #15610 (770f67b) into master (2be52c0) will increase coverage by 0.08%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master   #15610      +/-   ##
==========================================
+ Coverage   76.88%   76.96%   +0.08%     
==========================================
  Files         976      977       +1     
  Lines       51320    51419      +99     
  Branches     6907     6907              
==========================================
+ Hits        39458    39577     +119     
+ Misses      11643    11623      -20     
  Partials      219      219              

Flag	Coverage Δ
hive	81.28% <100.00%> (-0.01%)	⬇️
mysql	81.54% <100.00%> (-0.02%)	⬇️
postgres	81.56% <100.00%> (-0.02%)	⬇️
presto	81.27% <100.00%> (?)
python	82.10% <100.00%> (+0.14%)	⬆️
sqlite	81.18% <100.00%> (-0.02%)	⬇️

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

Impacted Files	Coverage Δ
superset/config.py	91.24% <100.00%> (+0.08%)	⬆️
superset/utils/webdriver.py	79.48% <100.00%> (+0.82%)	⬆️
superset/sql_lab.py	79.92% <0.00%> (-3.56%)	⬇️
superset/utils/core.py	88.25% <0.00%> (-0.84%)	⬇️
superset/views/core.py	75.01% <0.00%> (-0.11%)	⬇️
superset/views/base.py	75.86% <0.00%> (-0.10%)	⬇️
superset/connectors/base/models.py	88.49% <0.00%> (ø)
superset/utils/memoized.py	93.93% <0.00%> (ø)
superset/connectors/druid/models.py	82.81% <0.00%> (+0.01%)	⬆️
superset/databases/api.py	92.95% <0.00%> (+0.02%)	⬆️
... and 12 more

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[zhaoyongjie]

@u-aiaa please fix the pylint CI, Thanks!

[u-aiaa]

@zhaoyongjie fixed the pylint.