fix(filter)!: keep a comma inside a quoted list item

[pdevito3]

For later consideration in a major version. Do not merge now. #134 restored the v1.14.2 list split to keep v1.x compatible (restore commit 01e8b50). This PR re-applies c90861c. The captain decides on this PR separately.

Summary

• The list parser escapes , and \ in each quoted item before it joins the items.
• SplitListItems splits the list only on a comma that is not escaped, then trims each item. The in and not-in paths use it.

v1.14.2 behavior (and main)

The list text is split on every comma with Split(','). A comma inside a quoted item also splits the item.

New behavior

A quoted item is one item, also when it holds a comma. An unquoted list ([20, 30, 40]) does not change.

Example

FilterParser.ParseFilter<TestingPerson>("""Title ^^ ["Warm, with syrup", "a\b"]""");

• v1.14.2 and main: the list has three items, Warm, with syrup, and a\b. A person with the title Warm, with syrup does not match.
• This PR: the list has two items, Warm, with syrup and a\b. The person with the title Warm, with syrup matches.

Justification

Quotes mark where a value starts and stops. A comma inside the quotes is part of the value. The old split made it impossible to filter by a value that holds a comma.

Migration

A caller that put many values in one quoted item must write each value as its own quoted item: ["Warm", "with syrup"].

README

The in operator example now tells that a quoted list item can hold a comma.

Tests

These tests come back from main before #134:

• Unit FilterParsingRegressionTests.list_value_with_comma_is_split_into_items -> list_value_with_comma_is_one_item (theory, 5 cases: 4 cases expect one item again, the trim case is the same)
• Integration FilterParsingRegressionTests.list_value_with_comma_is_split_into_items -> list_value_with_comma_is_one_item (Postgres, the in and not-in rows swap back)

dotnet test: 470 unit tests and 297 Postgres integration tests (Testcontainers) pass, 0 failures.

Rebase on main

This branch is rebased on current main. On main, the list parser also returns a flag for a dot-only number in the list. The rebase keeps this flag and escapes each item value with EscapeListItem.