test: Add e2e testing

[hughhhh]

SUMMARY

BEFORE/AFTER SCREENSHOTS OR ANIMATED GIF

TESTING INSTRUCTIONS

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

[codecov]

Codecov Report

Merging #15376 (02aa26f) into pexdax/db-connection-ui (c283be6) will increase coverage by 0.27%.
The diff coverage is n/a.

@@                     Coverage Diff                     @@
##           pexdax/db-connection-ui   #15376      +/-   ##
===========================================================
+ Coverage                    76.75%   77.03%   +0.27%     
===========================================================
  Files                          972      971       -1     
  Lines                        50611    50325     -286     
  Branches                      6258     6140     -118     
===========================================================
- Hits                         38849    38766      -83     
+ Misses                       11556    11355     -201     
+ Partials                       206      204       -2     

Flag	Coverage Δ
hive	?
mysql	81.70% <ø> (ø)
postgres	81.72% <ø> (+<0.01%)	⬆️
presto	?
python	81.80% <ø> (-0.45%)	⬇️
sqlite	81.35% <ø> (ø)

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

Impacted Files	Coverage Δ
...c/views/CRUD/data/database/DatabaseModal/index.tsx	75.32% <ø> (+40.76%)	⬆️
superset/db_engines/hive.py	0.00% <0.00%> (-82.15%)	⬇️
superset/db_engine_specs/hive.py	69.20% <0.00%> (-17.21%)	⬇️
superset/db_engine_specs/presto.py	83.36% <0.00%> (-6.95%)	⬇️
superset/views/database/mixins.py	81.03% <0.00%> (-1.73%)	⬇️
superset/connectors/sqla/models.py	88.15% <0.00%> (-1.66%)	⬇️
superset/db_engine_specs/base.py	88.14% <0.00%> (-0.40%)	⬇️
superset/models/core.py	89.76% <0.00%> (-0.27%)	⬇️
superset/utils/core.py	88.93% <0.00%> (-0.13%)	⬇️
superset-frontend/src/components/Icon/index.tsx	100.00% <0.00%> (ø)
... and 12 more

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