Remove unused JS logic in email sharing

[kasparsd]

Fixes #1223

Changes proposed in this Pull Request:

• Remove the JS that was previously removing a dummy input field value for spam protection.
• Print inline scripts that depend on jQuery after WP core is done with print_footer_scripts(). We are not using wp_add_inline_script() because all the display_footer() methods echo instead of return their output.

Testing instructions:

• Share a post via email. Ensure that the email was sent.

[grappler]

Thank you @kasparsd for created the PR. The changes make sense.

[zinigor]

Looks good, sharing via email works fine, no more JavaScript error when enqueueing jQuery in the footer.

[zinigor]

To test you need to make jQuery load in the footer, it can be done using a filter like this:

function wpse_173601_enqueue_scripts() {
    $wp_scripts = wp_scripts();
    $wp_scripts->add_data( 'jquery', 'group', 1 );
    $wp_scripts->add_data( 'jquery-core', 'group', 1 );
    $wp_scripts->add_data( 'jquery-migrate', 'group', 1 );
}
add_action( 'wp_enqueue_scripts', 'wpse_173601_enqueue_scripts', 20 );

Keep in mind that in order for jQuery to remain in the footer, it has to have no dependent scripts loading in the header. One such script is the related posts JS, which you may have to disable or enqueue in the footer as well.