Update wp_list_comments type parameter to allow array or string

[dshanske]

Right now, the options here are all, or a specific comment type. This should allow for multiple comment types as allowed in WP_Comment_Query

Trac Ticket: Core-55922

## Problem

• The current implementation of the wp_list_comments function restricts the type parameter to a single comment type as either an array or a string, limiting its flexibility for developers who need to query multiple comment types simultaneously.

## Solution

• This enhancement introduces support for both arrays and strings in the type parameter of the wp_list_comments function. This update leverages the capabilities provided by WP_Comment_Query, allowing developers to specify comment types either as an array of types or as a single type string in a single query efficiently.

## Changes Made

• Code Enhancement: Updated the wp_list_comments function to accept both arrays and strings for the type parameter.

• Backend Implementation: Enhanced comment query handling to accommodate arrays and strings passed to the type parameter.

## Impact

• Enhanced Flexibility: Developers can now specify comment types using either an array of types or a single type string in the wp_list_comments function.

• Improved Query Capabilities: Facilitates querying multiple comment types simultaneously, leveraging the capabilities of WP_Comment_Query.

• Expanded Usage Scenarios: Supports a wider range of use cases where querying comments from multiple types is required within a single function call.

• Backward Compatibility: Ensures compatibility with existing usage of the wp_list_comments function by retaining support for single type string parameter.