Typecast bugfix

[Anish9901]

#4821 introduced a regression in which the appropriate cast_options parameter wasn't passed for __msar.build_cast_expr from within msar.set_old_col_default this led to a bug where retyping a column with non-dynamic defaults would result in the following error:

UndefinedFunction: function __msar.build_cast_expr(text, text) does not exist LINE 1: format('SELECT %s', __msar.build_cast_expr(old_default, new_... ^ 
HINT: No function matches the given name and argument types. You might need to add explicit type casts.
QUERY: format('SELECT %s', __msar.build_cast_expr(old_default, new_type)) CONTEXT: PL/pgSQL function msar.set_old_col_default(regclass,smallint,text,text,boolean,jsonb) line 20 at EXECUTE SQL statement "SELECT msar.set_old_col_default(tab_id, col.attnum, col.old_default, col.new_type, is_default_dynamic, col.cast_options)" PL/pgSQL function msar.alter_columns(oid,jsonb) line 78 at PERFORM

We already had tests to ensure type casting a column with a non-dynamic default value would preserve the default and doesn't error but msar.is_default_possibly_dynamic wrongly classified the non-dynamic default as dynamic which is why we didn't catch the aformentioned bug earlier. I've fixed the test setup so that msar.is_default_possibly_dynamic correctly classifies the defaults.

Another bug that was introduced was related to typecasting numeric or mathesar_money inferred columns to other types during the import preview.

• Casting numeric(inferred) --> mathesar_money wasn't possible as the cast_options didn't contain curr_pref & curr_suff as the inferred column was numeric.
• Casting mathesar_money(inferred) --> numeric is still not possible as this is a lossy cast if there are currency symbols in the data.

The added tests shows both of these cases.

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[mathemancer]

Nice work.

[mathemancer]

@zackkrida I'll leave it to you to figure out where/how to merge this. Specifically, I suppose you should make a branch off of master for 0.7.1 (since we don't want to keep any post-0.7.0 changes in develop right now) and rebase this onto that, then merge back into it?

[zackkrida]

I cherry-picked @Anish9901's commits and merged to a 0.7.1 branch based off of master.