Post meta does not imported due to slashes. Added wp_slash to the post and post meta.

[maheshwaghmare]

How to reproduce the issue?

1. I have create the page with Elementor.
2. Added the markup in widget like - <h3 class="elementor-heading-title elementor-size-default elementor-inline-editingpen " contenteditable="true "data-elementor-setting-key=.
3. I have exported the XML from - Tools > Export.
4. Trying to import it with the WordPress Importer v2.

It skip the page. Because the post meta is not unserialize. Line 1167

Sample page post meta while I have debugging.

{
    "id": "4b41ce4",
    "elType": "widget",
    "settings":
    {
    	"editor": "<h3 class="elementor-heading-title elementor-size-default elementor-inline-editingpen " contenteditable="true "data-elementor-setting-key="..

Quick Fix

I have used below filters to quick fix the issue and created this PR.

add_filter('wp_import_post_data_processed', function( $postdata, $data ) {
	return wp_slash( $postdata );
}, 99, 2 );

add_filter('wxr_importer.pre_process.post_meta', function( $meta_item, $post_id ) {
	return wp_slash( $meta_item );
}, 99, 2 );

Why this PR?

Because, If I imported the XML with the OLD WordPoress Importer it import the XML which DOES NOT imported with the NEW WordPoress Importer 2.

After debugging I found that the $postdata have not added wp_slash() which is added in old importer $postdata. It is missing from the $meta_item too. I have added both in this patch.

[rmccue]

Thanks! Closing in favour of #174 for a best practice approach.