fix(dataset): use sqlglot for DML check

[betodealmeida]

SUMMARY

Use sqlglot when getting column metadata for a virtual dataset. We currently use sqlglot to check for DML in SQL Lab, but when we save a query as a dataset we're still using sqlparse.

Part of SIP-117.

BEFORE/AFTER SCREENSHOTS OR ANIMATED GIF

N/A

TESTING INSTRUCTIONS

Run this query in SQL Lab:

with source as ( select 1 as one ) select * from source

This query is flagged incorrectly as DML by sqlparse, but not by sqlglot.

After running, save the query as a dataset. It should work, but currently it fails because sqlparse flags the query as having DML.

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