Properly deparse exprs that might appear in some DDLs

[onurctirtir]

e.g.:

CREATE SCHEMA my_schema;
CREATE TYPE my_schema.my_dt AS ENUM ('1','2','3');

CREATE FUNCTION my_schema.my_func()
RETURNS int
LANGUAGE sql
AS $$
SELECT 1;
$$;

CREATE TABLE referencing(a int);
SELECT create_distributed_table('referencing', 'a');

SET search_path TO my_schema, public;
ALTER TABLE referencing ADD check (a > my_func());

Also checked the other places we call deparse_expression() and all except the references in PreprocessAlterPolicyStmt() seem to be fine, so fixed them as well.

DESCRIPTION: Fixes a bug that might cause applying some DDLs on shards incorrectly

TODO: needs tests

[onderkalaci]

we should probably have deparse_expression_qualified or such

[codecov]

Codecov Report

Merging #7245 (15e65db) into main (83e3fb8) will decrease coverage by 3.66%.
Report is 4 commits behind head on main.
The diff coverage is 100.00%.

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  Files         275      275              
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  Branches        0     7423    +7423     
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- Hits        55495    53371    -2124     
- Misses       4032     4080      +48     
- Partials        0     2131    +2131