ClickHouse: Support tuple element access by index

[s5dsn-eqee]

ClickHouse allows accessing tuple elements by 1-based index with dot syntax:

https://clickhouse.com/docs/sql-reference/data-types/tuple#addressing-tuple-elements

SELECT t.1 FROM (SELECT (1, 'a') AS t)
SELECT (1, 'a').1
SELECT tuple(1, 'a').2
SELECT arr[1].1 FROM t

All of these fail with ClickHouseDialect:

sql parser error: Expected: end of statement, found: .1 at Line: 1, Column: 9

The tokenizer reads .1 after an identifier, ) or ] as a float literal instead of a period followed by an integer, so the compound field access parser never sees it. Expected AST is Expr::CompoundFieldAccess with AccessExpr::Dot(Expr::Value(Number(1))), which is the shape the parser already produces for x . 1 written with spaces.