fix: sqlparse fallback for formatting queries

[betodealmeida]

SUMMARY

An improvement to #30350.

Today, when a DB engine spec has no corresponding sqlglot dialect, we use a generic one to parse queries, which works fine. When converting the AST back to a string to pretty-print SQL, though, we hit a problem: in some databases the query becomes invalid. For example, this Firebolt query:

SELECT col FROM t WHERE col NOT IN (1, 2);

Gets formatted to:

SELECT col FROM t WHERE NOT col IN (1, 2);

While equivalent, the latter is invalid in Firebolt.

The long term solution is to add a Firebolt dialect to sqlglot, at least handling this edge case. As a more generic solution, this PR implements logic where, when a DB engine spec doesn't have a corresponding dialect in sqlglot, the query is pretty-printed using sqlparse.format. This way we have the strictness and correctness of sqlglot when parsing queries, and the leniency of sqlparse when formatting them.

BEFORE/AFTER SCREENSHOTS OR ANIMATED GIF

N/A

TESTING INSTRUCTIONS

Added unit tests covering the problem.

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