chore: Add tests to SQL lab button components

[diegomedina248]

SUMMARY

Made the following changes:

• EstimateQueryCostButton: added missing tests
• ExploreCtasResultsButton: added missing tests
• ExploreResultsButton: converted tests to RTL

BEFORE/AFTER SCREENSHOTS OR ANIMATED GIF

TESTING INSTRUCTIONS

ADDITIONAL INFORMATION

• Has associated issue:
• Required feature flags:
• 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 #22916 (747b52a) into master (b94052e) will increase coverage by 0.06%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master   #22916      +/-   ##
==========================================
+ Coverage   67.25%   67.31%   +0.06%     
==========================================
  Files        1876     1876              
  Lines       72066    72066              
  Branches     7869     7869              
==========================================
+ Hits        48470    48514      +44     
+ Misses      21578    21534      -44     
  Partials     2018     2018              

Flag	Coverage Δ
hive	52.71% <ø> (ø)
mysql	78.68% <ø> (ø)
postgres	78.75% <ø> (?)
presto	52.61% <ø> (ø)
python	81.97% <ø> (+0.12%)	⬆️
sqlite	77.08% <ø> (?)
unit	51.70% <ø> (ø)

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

Impacted Files	Coverage Δ
...lLab/components/ExploreCtasResultsButton/index.tsx	8.33% <ø> (ø)
...c/SqlLab/components/ExploreResultsButton/index.tsx	100.00% <ø> (ø)
superset/databases/api.py	91.30% <0.00%> (+0.27%)	⬆️
superset/db_engine_specs/base.py	90.21% <0.00%> (+0.31%)	⬆️
superset/reports/commands/execute.py	92.00% <0.00%> (+0.33%)	⬆️
superset/views/base_api.py	98.44% <0.00%> (+0.38%)	⬆️
superset/common/query_object.py	94.35% <0.00%> (+0.51%)	⬆️
superset/sqllab/api.py	100.00% <0.00%> (+1.19%)	⬆️
superset/commands/importers/v1/utils.py	93.50% <0.00%> (+1.29%)	⬆️
superset/result_set.py	97.87% <0.00%> (+1.41%)	⬆️
... and 10 more

📣 We’re building smart automated test selection to slash your CI/CD build times. Learn more

[rusackas]

LGTM, but adding more reviewers for second opinions if they have time.

[Antonio-RiveroMartnez]

LGTM