fix: add order by for bar charts

[bryanck]

SUMMARY

This adds an order by clause for the bar chart, ordering by the first metric descending. Without the ordering, the query will return an arbitrary set of rows if the query is limited, rather than the top N rows.

BEFORE/AFTER SCREENSHOTS OR ANIMATED GIF

TEST PLAN

Create a bar chart against a dataset. Limit the result to something less than the total number of rows. The top N rows, based on the metric, should be returned.

ADDITIONAL INFORMATION

Fixes #12622

• Has associated issue: [explore]Bar chart doesn't sort descending anymore #12622
• Changes UI
• Requires DB Migration.
• Confirm DB Migration upgrade and downgrade tested.
• Introduces new feature or API
• Removes existing feature or API

[codecov-io]

Codecov Report

Merging #12661 (e72968d) into master (734fb75) will decrease coverage by 3.63%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master   #12661      +/-   ##
==========================================
- Coverage   66.85%   63.21%   -3.64%     
==========================================
  Files        1018      486     -532     
  Lines       49776    29983   -19793     
  Branches     4869        0    -4869     
==========================================
- Hits        33278    18954   -14324     
+ Misses      16375    11029    -5346     
+ Partials      123        0     -123     

Flag	Coverage Δ
cypress	?
javascript	?
python	63.21% <100.00%> (-0.80%)	⬇️

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

Impacted Files	Coverage Δ
superset/viz.py	60.02% <100.00%> (+0.02%)	⬆️
superset/db_engines/hive.py	0.00% <0.00%> (-85.72%)	⬇️
superset/sql_validators/postgres.py	50.00% <0.00%> (-50.00%)	⬇️
superset/db_engine_specs/hive.py	54.61% <0.00%> (-29.24%)	⬇️
superset/databases/commands/create.py	83.67% <0.00%> (-8.17%)	⬇️
superset/databases/commands/update.py	85.71% <0.00%> (-8.17%)	⬇️
superset/connectors/sqla/models.py	84.31% <0.00%> (-6.28%)	⬇️
superset/db_engine_specs/sqlite.py	90.62% <0.00%> (-6.25%)	⬇️
superset/databases/commands/test_connection.py	84.78% <0.00%> (-4.35%)	⬇️
superset/utils/celery.py	96.42% <0.00%> (-3.58%)	⬇️
... and 543 more

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[villebro]

Thanks for the fix @bryanck !

[bryanck]

Sure, though I noticed this is happening elsewhere, so I'll have another PR (word cloud, multi-line graphs)