Fix CTE join fix with df.alias

[sfc-gh-aalam]

1. Which Jira issue is this PR addressing? Make sure that there is an accompanying issue to your PR.

   Fixes SNOW-NNNNNNN

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[sfc-gh-aling]

deepcopy is not equivalent to update.

if there is a "key" in self.df_aliased_col_name_to_real_col_name but not in self.from_.df_aliased_col_name_to_real_col_name.

the previous update will keep the "key", but deepcopy will discard the "key".

will this cause issue?

[sfc-gh-aalam]

I agree. However this is the __init__ method. At this point, self.df_aliased_col_name_to_real_col_name should be empty generated by Selectable init

snowpark-python/src/snowflake/snowpark/_internal/analyzer/select_statement.py

Line 265 in 1a51219

self.df_aliased_col_name_to_real_col_name = (