feat: create dtype option for csv upload

[eschutho]

SUMMARY

Redshift automatically converts all text columns to a varchar(256) which means for uploads, and in particular csv uploads for this case, the only way to upload a column with a large text field is to first create the table in sql lab with the correct column definitions and then upload to that existing table and replace the data. This pr adds a new dtype field for the upload, and using the "string" property, converts any field of this type to a varchar(max) for redshift. Currently all string types are uploaded as "object", so this change shouldn't impact any uploads that aren't explicitly passing the "string" property. We could extend this to other dbs, but it looks like the default behavior is for uploaded string columns to be converted to text.

BEFORE/AFTER SCREENSHOTS OR ANIMATED GIF

After: (added a new field)

In this example, I updated just the column type to nvarchar(max) by passing {"Question":"string"} into the upload form. The other string field remains as varchar(256).

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 #23716 (2b6a084) into master (42e8d1b) will increase coverage by 2.01%.
The diff coverage is 65.54%.

❗ Current head 2b6a084 differs from pull request most recent head ef00cd0. Consider uploading reports for the commit ef00cd0 to get more accurate results

@@            Coverage Diff             @@
##           master   #23716      +/-   ##
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+ Coverage   65.96%   67.98%   +2.01%     
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  Files        1907     1936      +29     
  Lines       73590    74928    +1338     
  Branches     7982     8140     +158     
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+ Hits        48546    50942    +2396     
+ Misses      22996    21894    -1102     
- Partials     2048     2092      +44     

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hive	53.00% <ø> (+0.26%)	⬆️
mysql	78.80% <ø> (+0.39%)	⬆️
postgres	78.87% <ø> (+0.37%)	⬆️
presto	52.92% <ø> (+0.25%)	⬆️
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sqlite	77.39% <ø> (?)
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Impacted Files	Coverage Δ
...ackages/superset-ui-chart-controls/src/fixtures.ts	100.00% <ø> (ø)
...t-ui-chart-controls/src/shared-controls/mixins.tsx	16.66% <ø> (ø)
...d/packages/superset-ui-chart-controls/src/types.ts	100.00% <ø> (ø)
.../packages/superset-ui-core/src/chart/types/Base.ts	100.00% <ø> (ø)
...s/superset-ui-core/src/components/SafeMarkdown.tsx	85.71% <0.00%> (+19.04%)	⬆️
...ackages/superset-ui-core/src/query/types/Filter.ts	100.00% <ø> (ø)
...ackages/superset-ui-core/src/utils/featureFlags.ts	100.00% <ø> (ø)
...s/legacy-plugin-chart-country-map/src/countries.ts	100.00% <ø> (ø)
...plugins/legacy-plugin-chart-heatmap/src/Heatmap.js	0.00% <0.00%> (ø)
...gins/legacy-plugin-chart-world-map/src/WorldMap.js	0.00% <0.00%> (ø)
... and 141 more

... and 332 files with indirect coverage changes

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[betodealmeida]

This looks great!

[betodealmeida]

I would use a concrete example here, something like:

Suggested change

	"A dictionary with column names and their data types if you need to change the defaults. Example: {“Column”:“data type”}"
	"A dictionary with column names and their data types if you need to change the defaults. Example: {“user_id”:“integer”}"

[eschutho]

good idea!