feat(optimizer): Annotate type for snowflake CBRT function

[fivetran-amrutabhimsenayachit]

Annotate type for snowflake CBRT function

Documentation:
https://docs.snowflake.com/en/sql-reference/functions/cbrt

Mapped FLOAT return type to DOUBLE as per https://docs.snowflake.com/en/sql-reference/data-types-numeric#double-double-precision-real , https://docs.snowflake.com/en/sql-reference/data-types-numeric#float-float4-float8

[Copilot]

Pull Request Overview

This PR adds type annotation support for the CBRT (cube root) function in the Snowflake dialect, enabling the optimizer to correctly infer that CBRT returns a DOUBLE type.

• Adds CBRT function to Snowflake's DOUBLE type mapping in the type annotation system
• Includes test coverage for the CBRT function type annotation
• Adds validation test for CBRT function parsing

Reviewed Changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
sqlglot/dialects/snowflake.py	Maps CBRT function to DOUBLE type in Snowflake dialect
tests/fixtures/optimizer/annotate_functions.sql	Adds test case verifying CBRT returns DOUBLE type
tests/dialects/test_snowflake.py	Adds validation test for CBRT function parsing

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