.join_where() should error when _right does not exist.

[cmdlineluser]

Checks

• I have checked that this issue has not already been reported.
• I have confirmed this bug exists on the latest version of Polars.

Reproducible example

import polars as pl

df = pl.DataFrame({"id": [1, 2]})

df.join_where(df, pl.col("id") >= pl.col("id_right"))
# shape: (3, 2)
# ┌─────┬──────────┐
# │ id  ┆ id_right │
# │ --- ┆ ---      │
# │ i64 ┆ i64      │
# ╞═════╪══════════╡
# │ 1   ┆ 1        │
# │ 2   ┆ 1        │
# │ 2   ┆ 2        │
# └─────┴──────────┘

Log output

No response

Issue description

As per @ritchie46 on Discord - this should error as predicates refer to the tables before the join and id_right does not yet exist in this example.

Expected behavior

ColumnNotFoundError

Installed versions

main