BigQuery: enable FROM-first SELECT (pipe syntax entry form)

[moshap-firebolt]

Enables supports_from_first_select for BigQueryDialect so FROM t |> … (GoogleSQL's canonical pipe entry form) and plain FROM t parse. Matches ClickHouse/DuckDB/Generic. 55 bigquery tests pass.

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Note

Low Risk
Single dialect capability flag with no auth, data, or core parser logic changes beyond BigQuery parsing behavior.

Overview
BigQuery now opts into FROM-first SELECT parsing by implementing supports_from_first_select on BigQueryDialect (returns true).

This aligns BigQuery with ClickHouse, DuckDB, and Generic dialects so the parser accepts GoogleSQL’s canonical pipe entry form (FROM t |> WHERE …) and plain FROM-leading queries, complementing the existing supports_pipe_operator flag.

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[moshap-firebolt]

Post-hoc review note (flagging for visibility): this was merged into firebolt/v0.62.0-patches as part of packdb PR firebolt-analytics/packdb#24299 (BigQuery pipe query syntax).

Scope: a single additive 7-line change — BigQueryDialect::supports_from_first_select() -> true, so GoogleSQL's canonical FROM t |> … pipe entry form (and plain FROM t) parse, matching ClickHouse/DuckDB/Generic. No behavior change for any other dialect.

Verification: cargo test --test sqlparser_bigquery (55 tests) passed; FROM-first + SELECT-first pipe queries parse correctly.

Rollback if desired: firebolt/v0.62.0-patches fast-forwarded eee77cb → 26b5faa, so it resets cleanly to eee77cb; the feature branch moshap/bigquery-from-first-select still exists. Please review and revert if you'd prefer this go through a different process.